Merge pull request #34 from ava-labs/devv0.3.0-rc.5

Dev

21 files changed, 1652 insertions, 1205 deletions

diff --git a/core/vm/common.go b/core/vm/common.go
index ead30fc..90ba4a4 100644
--- a/core/vm/common.go
+++ b/core/vm/common.go
@@ -17,15 +17,14 @@
 package vm
 
 import (
-	"math/big"
-
-	"github.com/ava-labs/go-ethereum/common"
-	"github.com/ava-labs/go-ethereum/common/math"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/math"
+	"github.com/holiman/uint256"
 )
 
 // calcMemSize64 calculates the required memory size, and returns
 // the size and whether the result overflowed uint64
-func calcMemSize64(off, l *big.Int) (uint64, bool) {
+func calcMemSize64(off, l *uint256.Int) (uint64, bool) {
 	if !l.IsUint64() {
 		return 0, true
 	}
@@ -35,16 +34,16 @@ func calcMemSize64(off, l *big.Int) (uint64, bool) {
 // calcMemSize64WithUint calculates the required memory size, and returns
 // the size and whether the result overflowed uint64
 // Identical to calcMemSize64, but length is a uint64
-func calcMemSize64WithUint(off *big.Int, length64 uint64) (uint64, bool) {
+func calcMemSize64WithUint(off *uint256.Int, length64 uint64) (uint64, bool) {
 	// if length is zero, memsize is always zero, regardless of offset
 	if length64 == 0 {
 		return 0, false
 	}
 	// Check that offset doesn't overflow
-	if !off.IsUint64() {
+	offset64, overflow := off.Uint64WithOverflow()
+	if overflow {
 		return 0, true
 	}
-	offset64 := off.Uint64()
 	val := offset64 + length64
 	// if value < either of it's parts, then it overflowed
 	return val, val < offset64
@@ -64,22 +63,6 @@ func getData(data []byte, start uint64, size uint64) []byte {
 	return common.RightPadBytes(data[start:end], int(size))
 }
 
-// getDataBig returns a slice from the data based on the start and size and pads
-// up to size with zero's. This function is overflow safe.
-func getDataBig(data []byte, start *big.Int, size *big.Int) []byte {
-	dlen := big.NewInt(int64(len(data)))
-
-	s := math.BigMin(start, dlen)
-	e := math.BigMin(new(big.Int).Add(s, size), dlen)
-	return common.RightPadBytes(data[s.Uint64():e.Uint64()], int(size.Uint64()))
-}
-
-// bigUint64 returns the integer casted to a uint64 and returns whether it
-// overflowed in the process.
-func bigUint64(v *big.Int) (uint64, bool) {
-	return v.Uint64(), !v.IsUint64()
-}
-
 // toWordSize returns the ceiled word size required for memory expansion.
 func toWordSize(size uint64) uint64 {
 	if size > math.MaxUint64-31 {
diff --git a/core/vm/contract.go b/core/vm/contract.go
index ed17402..915193d 100644
--- a/core/vm/contract.go
+++ b/core/vm/contract.go
@@ -19,7 +19,8 @@ package vm
 import (
 	"math/big"
 
-	"github.com/ava-labs/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/holiman/uint256"
 )
 
 // ContractRef is a reference to the contract's backing object
@@ -81,18 +82,43 @@ func NewContract(caller ContractRef, object ContractRef, value *big.Int, gas uin
 	return c
 }
 
-func (c *Contract) validJumpdest(dest *big.Int) bool {
-	udest := dest.Uint64()
+func (c *Contract) validJumpdest(dest *uint256.Int) bool {
+	udest, overflow := dest.Uint64WithOverflow()
 	// PC cannot go beyond len(code) and certainly can't be bigger than 63bits.
 	// Don't bother checking for JUMPDEST in that case.
-	if dest.BitLen() >= 63 || udest >= uint64(len(c.Code)) {
+	if overflow || udest >= uint64(len(c.Code)) {
 		return false
 	}
 	// Only JUMPDESTs allowed for destinations
 	if OpCode(c.Code[udest]) != JUMPDEST {
 		return false
 	}
+	return c.isCode(udest)
+}
+
+func (c *Contract) validJumpSubdest(udest uint64) bool {
+	// PC cannot go beyond len(code) and certainly can't be bigger than 63 bits.
+	// Don't bother checking for BEGINSUB in that case.
+	if int64(udest) < 0 || udest >= uint64(len(c.Code)) {
+		return false
+	}
+	// Only BEGINSUBs allowed for destinations
+	if OpCode(c.Code[udest]) != BEGINSUB {
+		return false
+	}
+	return c.isCode(udest)
+}
+
+// isCode returns true if the provided PC location is an actual opcode, as
+// opposed to a data-segment following a PUSHN operation.
+func (c *Contract) isCode(udest uint64) bool {
+	// Do we already have an analysis laying around?
+	if c.analysis != nil {
+		return c.analysis.codeSegment(udest)
+	}
 	// Do we have a contract hash already?
+	// If we do have a hash, that means it's a 'regular' contract. For regular
+	// contracts ( not temporary initcode), we store the analysis in a map
 	if c.CodeHash != (common.Hash{}) {
 		// Does parent context have the analysis?
 		analysis, exist := c.jumpdests[c.CodeHash]
@@ -102,6 +128,8 @@ func (c *Contract) validJumpdest(dest *big.Int) bool {
 			analysis = codeBitmap(c.Code)
 			c.jumpdests[c.CodeHash] = analysis
 		}
+		// Also stash it in current contract for faster access
+		c.analysis = analysis
 		return analysis.codeSegment(udest)
 	}
 	// We don't have the code hash, most likely a piece of initcode not already
diff --git a/core/vm/contracts.go b/core/vm/contracts.go
index 54eab4e..9827bac 100644
--- a/core/vm/contracts.go
+++ b/core/vm/contracts.go
@@ -23,11 +23,14 @@ import (
 	"math/big"
 
 	"github.com/ava-labs/coreth/params"
-	"github.com/ava-labs/go-ethereum/common"
-	"github.com/ava-labs/go-ethereum/common/math"
-	"github.com/ava-labs/go-ethereum/crypto"
-	"github.com/ava-labs/go-ethereum/crypto/blake2b"
-	"github.com/ava-labs/go-ethereum/crypto/bn256"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/math"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/crypto/blake2b"
+	"github.com/ethereum/go-ethereum/crypto/bls12381"
+	"github.com/ethereum/go-ethereum/crypto/bn256"
+
+	//lint:ignore SA1019 Needed for precompile
 	"golang.org/x/crypto/ripemd160"
 )
 
@@ -75,13 +78,42 @@ var PrecompiledContractsIstanbul = map[common.Address]PrecompiledContract{
 	common.BytesToAddress([]byte{9}): &blake2F{},
 }
 
+// PrecompiledContractsYoloV1 contains the default set of pre-compiled Ethereum
+// contracts used in the Yolo v1 test release.
+var PrecompiledContractsYoloV1 = map[common.Address]PrecompiledContract{
+	common.BytesToAddress([]byte{1}):  &ecrecover{},
+	common.BytesToAddress([]byte{2}):  &sha256hash{},
+	common.BytesToAddress([]byte{3}):  &ripemd160hash{},
+	common.BytesToAddress([]byte{4}):  &dataCopy{},
+	common.BytesToAddress([]byte{5}):  &bigModExp{},
+	common.BytesToAddress([]byte{6}):  &bn256AddIstanbul{},
+	common.BytesToAddress([]byte{7}):  &bn256ScalarMulIstanbul{},
+	common.BytesToAddress([]byte{8}):  &bn256PairingIstanbul{},
+	common.BytesToAddress([]byte{9}):  &blake2F{},
+	common.BytesToAddress([]byte{10}): &bls12381G1Add{},
+	common.BytesToAddress([]byte{11}): &bls12381G1Mul{},
+	common.BytesToAddress([]byte{12}): &bls12381G1MultiExp{},
+	common.BytesToAddress([]byte{13}): &bls12381G2Add{},
+	common.BytesToAddress([]byte{14}): &bls12381G2Mul{},
+	common.BytesToAddress([]byte{15}): &bls12381G2MultiExp{},
+	common.BytesToAddress([]byte{16}): &bls12381Pairing{},
+	common.BytesToAddress([]byte{17}): &bls12381MapG1{},
+	common.BytesToAddress([]byte{18}): &bls12381MapG2{},
+}
+
 // RunPrecompiledContract runs and evaluates the output of a precompiled contract.
-func RunPrecompiledContract(p PrecompiledContract, input []byte, contract *Contract) (ret []byte, err error) {
-	gas := p.RequiredGas(input)
-	if contract.UseGas(gas) {
-		return p.Run(input)
+// It returns
+// - the returned bytes,
+// - the _remaining_ gas,
+// - any error that occurred
+func RunPrecompiledContract(p PrecompiledContract, input []byte, suppliedGas uint64) (ret []byte, remainingGas uint64, err error) {
+	gasCost := p.RequiredGas(input)
+	if suppliedGas < gasCost {
+		return nil, 0, ErrOutOfGas
 	}
-	return nil, ErrOutOfGas
+	suppliedGas -= gasCost
+	output, err := p.Run(input)
+	return output, suppliedGas, err
 }
 
 // ECRECOVER implemented as a native contract.
@@ -106,8 +138,13 @@ func (c *ecrecover) Run(input []byte) ([]byte, error) {
 	if !allZero(input[32:63]) || !crypto.ValidateSignatureValues(v, r, s, false) {
 		return nil, nil
 	}
+	// We must make sure not to modify the 'input', so placing the 'v' along with
+	// the signature needs to be done on a new allocation
+	sig := make([]byte, 65)
+	copy(sig, input[64:128])
+	sig[64] = v
 	// v needs to be at the end for libsecp256k1
-	pubKey, err := crypto.Ecrecover(input[:32], append(input[64:128], v))
+	pubKey, err := crypto.Ecrecover(input[:32], sig)
 	// make sure the public key is a valid one
 	if err != nil {
 		return nil, nil
@@ -166,6 +203,7 @@ func (c *dataCopy) Run(in []byte) ([]byte, error) {
 type bigModExp struct{}
 
 var (
+	big0      = big.NewInt(0)
 	big1      = big.NewInt(1)
 	big4      = big.NewInt(4)
 	big8      = big.NewInt(8)
@@ -458,7 +496,7 @@ var (
 )
 
 func (c *blake2F) Run(input []byte) ([]byte, error) {
-	// Make sure the input is valid (correct lenth and final flag)
+	// Make sure the input is valid (correct length and final flag)
 	if len(input) != blake2FInputLength {
 		return nil, errBlake2FInvalidInputLength
 	}
@@ -495,3 +533,428 @@ func (c *blake2F) Run(input []byte) ([]byte, error) {
 	}
 	return output, nil
 }
+
+var (
+	errBLS12381InvalidInputLength          = errors.New("invalid input length")
+	errBLS12381InvalidFieldElementTopBytes = errors.New("invalid field element top bytes")
+	errBLS12381G1PointSubgroup             = errors.New("g1 point is not on correct subgroup")
+	errBLS12381G2PointSubgroup             = errors.New("g2 point is not on correct subgroup")
+)
+
+// bls12381G1Add implements EIP-2537 G1Add precompile.
+type bls12381G1Add struct{}
+
+// RequiredGas returns the gas required to execute the pre-compiled contract.
+func (c *bls12381G1Add) RequiredGas(input []byte) uint64 {
+	return params.Bls12381G1AddGas
+}
+
+func (c *bls12381G1Add) Run(input []byte) ([]byte, error) {
+	// Implements EIP-2537 G1Add precompile.
+	// > G1 addition call expects `256` bytes as an input that is interpreted as byte concatenation of two G1 points (`128` bytes each).
+	// > Output is an encoding of addition operation result - single G1 point (`128` bytes).
+	if len(input) != 256 {
+		return nil, errBLS12381InvalidInputLength
+	}
+	var err error
+	var p0, p1 *bls12381.PointG1
+
+	// Initialize G1
+	g := bls12381.NewG1()
+
+	// Decode G1 point p_0
+	if p0, err = g.DecodePoint(input[:128]); err != nil {
+		return nil, err
+	}
+	// Decode G1 point p_1
+	if p1, err = g.DecodePoint(input[128:]); err != nil {
+		return nil, err
+	}
+
+	// Compute r = p_0 + p_1
+	r := g.New()
+	g.Add(r, p0, p1)
+
+	// Encode the G1 point result into 128 bytes
+	return g.EncodePoint(r), nil
+}
+
+// bls12381G1Mul implements EIP-2537 G1Mul precompile.
+type bls12381G1Mul struct{}
+
+// RequiredGas returns the gas required to execute the pre-compiled contract.
+func (c *bls12381G1Mul) RequiredGas(input []byte) uint64 {
+	return params.Bls12381G1MulGas
+}
+
+func (c *bls12381G1Mul) Run(input []byte) ([]byte, error) {
+	// Implements EIP-2537 G1Mul precompile.
+	// > G1 multiplication call expects `160` bytes as an input that is interpreted as byte concatenation of encoding of G1 point (`128` bytes) and encoding of a scalar value (`32` bytes).
+	// > Output is an encoding of multiplication operation result - single G1 point (`128` bytes).
+	if len(input) != 160 {
+		return nil, errBLS12381InvalidInputLength
+	}
+	var err error
+	var p0 *bls12381.PointG1
+
+	// Initialize G1
+	g := bls12381.NewG1()
+
+	// Decode G1 point
+	if p0, err = g.DecodePoint(input[:128]); err != nil {
+		return nil, err
+	}
+	// Decode scalar value
+	e := new(big.Int).SetBytes(input[128:])
+
+	// Compute r = e * p_0
+	r := g.New()
+	g.MulScalar(r, p0, e)
+
+	// Encode the G1 point into 128 bytes
+	return g.EncodePoint(r), nil
+}
+
+// bls12381G1MultiExp implements EIP-2537 G1MultiExp precompile.
+type bls12381G1MultiExp struct{}
+
+// RequiredGas returns the gas required to execute the pre-compiled contract.
+func (c *bls12381G1MultiExp) RequiredGas(input []byte) uint64 {
+	// Calculate G1 point, scalar value pair length
+	k := len(input) / 160
+	if k == 0 {
+		// Return 0 gas for small input length
+		return 0
+	}
+	// Lookup discount value for G1 point, scalar value pair length
+	var discount uint64
+	if dLen := len(params.Bls12381MultiExpDiscountTable); k < dLen {
+		discount = params.Bls12381MultiExpDiscountTable[k-1]
+	} else {
+		discount = params.Bls12381MultiExpDiscountTable[dLen-1]
+	}
+	// Calculate gas and return the result
+	return (uint64(k) * params.Bls12381G1MulGas * discount) / 1000
+}
+
+func (c *bls12381G1MultiExp) Run(input []byte) ([]byte, error) {
+	// Implements EIP-2537 G1MultiExp precompile.
+	// G1 multiplication call expects `160*k` bytes as an input that is interpreted as byte concatenation of `k` slices each of them being a byte concatenation of encoding of G1 point (`128` bytes) and encoding of a scalar value (`32` bytes).
+	// Output is an encoding of multiexponentiation operation result - single G1 point (`128` bytes).
+	k := len(input) / 160
+	if len(input) == 0 || len(input)%160 != 0 {
+		return nil, errBLS12381InvalidInputLength
+	}
+	var err error
+	points := make([]*bls12381.PointG1, k)
+	scalars := make([]*big.Int, k)
+
+	// Initialize G1
+	g := bls12381.NewG1()
+
+	// Decode point scalar pairs
+	for i := 0; i < k; i++ {
+		off := 160 * i
+		t0, t1, t2 := off, off+128, off+160
+		// Decode G1 point
+		if points[i], err = g.DecodePoint(input[t0:t1]); err != nil {
+			return nil, err
+		}
+		// Decode scalar value
+		scalars[i] = new(big.Int).SetBytes(input[t1:t2])
+	}
+
+	// Compute r = e_0 * p_0 + e_1 * p_1 + ... + e_(k-1) * p_(k-1)
+	r := g.New()
+	g.MultiExp(r, points, scalars)
+
+	// Encode the G1 point to 128 bytes
+	return g.EncodePoint(r), nil
+}
+
+// bls12381G2Add implements EIP-2537 G2Add precompile.
+type bls12381G2Add struct{}
+
+// RequiredGas returns the gas required to execute the pre-compiled contract.
+func (c *bls12381G2Add) RequiredGas(input []byte) uint64 {
+	return params.Bls12381G2AddGas
+}
+
+func (c *bls12381G2Add) Run(input []byte) ([]byte, error) {
+	// Implements EIP-2537 G2Add precompile.
+	// > G2 addition call expects `512` bytes as an input that is interpreted as byte concatenation of two G2 points (`256` bytes each).
+	// > Output is an encoding of addition operation result - single G2 point (`256` bytes).
+	if len(input) != 512 {
+		return nil, errBLS12381InvalidInputLength
+	}
+	var err error
+	var p0, p1 *bls12381.PointG2
+
+	// Initialize G2
+	g := bls12381.NewG2()
+	r := g.New()
+
+	// Decode G2 point p_0
+	if p0, err = g.DecodePoint(input[:256]); err != nil {
+		return nil, err
+	}
+	// Decode G2 point p_1
+	if p1, err = g.DecodePoint(input[256:]); err != nil {
+		return nil, err
+	}
+
+	// Compute r = p_0 + p_1
+	g.Add(r, p0, p1)
+
+	// Encode the G2 point into 256 bytes
+	return g.EncodePoint(r), nil
+}
+
+// bls12381G2Mul implements EIP-2537 G2Mul precompile.
+type bls12381G2Mul struct{}
+
+// RequiredGas returns the gas required to execute the pre-compiled contract.
+func (c *bls12381G2Mul) RequiredGas(input []byte) uint64 {
+	return params.Bls12381G2MulGas
+}
+
+func (c *bls12381G2Mul) Run(input []byte) ([]byte, error) {
+	// Implements EIP-2537 G2MUL precompile logic.
+	// > G2 multiplication call expects `288` bytes as an input that is interpreted as byte concatenation of encoding of G2 point (`256` bytes) and encoding of a scalar value (`32` bytes).
+	// > Output is an encoding of multiplication operation result - single G2 point (`256` bytes).
+	if len(input) != 288 {
+		return nil, errBLS12381InvalidInputLength
+	}
+	var err error
+	var p0 *bls12381.PointG2
+
+	// Initialize G2
+	g := bls12381.NewG2()
+
+	// Decode G2 point
+	if p0, err = g.DecodePoint(input[:256]); err != nil {
+		return nil, err
+	}
+	// Decode scalar value
+	e := new(big.Int).SetBytes(input[256:])
+
+	// Compute r = e * p_0
+	r := g.New()
+	g.MulScalar(r, p0, e)
+
+	// Encode the G2 point into 256 bytes
+	return g.EncodePoint(r), nil
+}
+
+// bls12381G2MultiExp implements EIP-2537 G2MultiExp precompile.
+type bls12381G2MultiExp struct{}
+
+// RequiredGas returns the gas required to execute the pre-compiled contract.
+func (c *bls12381G2MultiExp) RequiredGas(input []byte) uint64 {
+	// Calculate G2 point, scalar value pair length
+	k := len(input) / 288
+	if k == 0 {
+		// Return 0 gas for small input length
+		return 0
+	}
+	// Lookup discount value for G2 point, scalar value pair length
+	var discount uint64
+	if dLen := len(params.Bls12381MultiExpDiscountTable); k < dLen {
+		discount = params.Bls12381MultiExpDiscountTable[k-1]
+	} else {
+		discount = params.Bls12381MultiExpDiscountTable[dLen-1]
+	}
+	// Calculate gas and return the result
+	return (uint64(k) * params.Bls12381G2MulGas * discount) / 1000
+}
+
+func (c *bls12381G2MultiExp) Run(input []byte) ([]byte, error) {
+	// Implements EIP-2537 G2MultiExp precompile logic
+	// > G2 multiplication call expects `288*k` bytes as an input that is interpreted as byte concatenation of `k` slices each of them being a byte concatenation of encoding of G2 point (`256` bytes) and encoding of a scalar value (`32` bytes).
+	// > Output is an encoding of multiexponentiation operation result - single G2 point (`256` bytes).
+	k := len(input) / 288
+	if len(input) == 0 || len(input)%288 != 0 {
+		return nil, errBLS12381InvalidInputLength
+	}
+	var err error
+	points := make([]*bls12381.PointG2, k)
+	scalars := make([]*big.Int, k)
+
+	// Initialize G2
+	g := bls12381.NewG2()
+
+	// Decode point scalar pairs
+	for i := 0; i < k; i++ {
+		off := 288 * i
+		t0, t1, t2 := off, off+256, off+288
+		// Decode G1 point
+		if points[i], err = g.DecodePoint(input[t0:t1]); err != nil {
+			return nil, err
+		}
+		// Decode scalar value
+		scalars[i] = new(big.Int).SetBytes(input[t1:t2])
+	}
+
+	// Compute r = e_0 * p_0 + e_1 * p_1 + ... + e_(k-1) * p_(k-1)
+	r := g.New()
+	g.MultiExp(r, points, scalars)
+
+	// Encode the G2 point to 256 bytes.
+	return g.EncodePoint(r), nil
+}
+
+// bls12381Pairing implements EIP-2537 Pairing precompile.
+type bls12381Pairing struct{}
+
+// RequiredGas returns the gas required to execute the pre-compiled contract.
+func (c *bls12381Pairing) RequiredGas(input []byte) uint64 {
+	return params.Bls12381PairingBaseGas + uint64(len(input)/384)*params.Bls12381PairingPerPairGas
+}
+
+func (c *bls12381Pairing) Run(input []byte) ([]byte, error) {
+	// Implements EIP-2537 Pairing precompile logic.
+	// > Pairing call expects `384*k` bytes as an inputs that is interpreted as byte concatenation of `k` slices. Each slice has the following structure:
+	// > - `128` bytes of G1 point encoding
+	// > - `256` bytes of G2 point encoding
+	// > Output is a `32` bytes where last single byte is `0x01` if pairing result is equal to multiplicative identity in a pairing target field and `0x00` otherwise
+	// > (which is equivalent of Big Endian encoding of Solidity values `uint256(1)` and `uin256(0)` respectively).
+	k := len(input) / 384
+	if len(input) == 0 || len(input)%384 != 0 {
+		return nil, errBLS12381InvalidInputLength
+	}
+
+	// Initialize BLS12-381 pairing engine
+	e := bls12381.NewPairingEngine()
+	g1, g2 := e.G1, e.G2
+
+	// Decode pairs
+	for i := 0; i < k; i++ {
+		off := 384 * i
+		t0, t1, t2 := off, off+128, off+384
+
+		// Decode G1 point
+		p1, err := g1.DecodePoint(input[t0:t1])
+		if err != nil {
+			return nil, err
+		}
+		// Decode G2 point
+		p2, err := g2.DecodePoint(input[t1:t2])
+		if err != nil {
+			return nil, err
+		}
+
+		// 'point is on curve' check already done,
+		// Here we need to apply subgroup checks.
+		if !g1.InCorrectSubgroup(p1) {
+			return nil, errBLS12381G1PointSubgroup
+		}
+		if !g2.InCorrectSubgroup(p2) {
+			return nil, errBLS12381G2PointSubgroup
+		}
+
+		// Update pairing engine with G1 and G2 ponits
+		e.AddPair(p1, p2)
+	}
+	// Prepare 32 byte output
+	out := make([]byte, 32)
+
+	// Compute pairing and set the result
+	if e.Check() {
+		out[31] = 1
+	}
+	return out, nil
+}
+
+// decodeBLS12381FieldElement decodes BLS12-381 elliptic curve field element.
+// Removes top 16 bytes of 64 byte input.
+func decodeBLS12381FieldElement(in []byte) ([]byte, error) {
+	if len(in) != 64 {
+		return nil, errors.New("invalid field element length")
+	}
+	// check top bytes
+	for i := 0; i < 16; i++ {
+		if in[i] != byte(0x00) {
+			return nil, errBLS12381InvalidFieldElementTopBytes
+		}
+	}
+	out := make([]byte, 48)
+	copy(out[:], in[16:])
+	return out, nil
+}
+
+// bls12381MapG1 implements EIP-2537 MapG1 precompile.
+type bls12381MapG1 struct{}
+
+// RequiredGas returns the gas required to execute the pre-compiled contract.
+func (c *bls12381MapG1) RequiredGas(input []byte) uint64 {
+	return params.Bls12381MapG1Gas
+}
+
+func (c *bls12381MapG1) Run(input []byte) ([]byte, error) {
+	// Implements EIP-2537 Map_To_G1 precompile.
+	// > Field-to-curve call expects `64` bytes an an input that is interpreted as a an element of the base field.
+	// > Output of this call is `128` bytes and is G1 point following respective encoding rules.
+	if len(input) != 64 {
+		return nil, errBLS12381InvalidInputLength
+	}
+
+	// Decode input field element
+	fe, err := decodeBLS12381FieldElement(input)
+	if err != nil {
+		return nil, err
+	}
+
+	// Initialize G1
+	g := bls12381.NewG1()
+
+	// Compute mapping
+	r, err := g.MapToCurve(fe)
+	if err != nil {
+		return nil, err
+	}
+
+	// Encode the G1 point to 128 bytes
+	return g.EncodePoint(r), nil
+}
+
+// bls12381MapG2 implements EIP-2537 MapG2 precompile.
+type bls12381MapG2 struct{}
+
+// RequiredGas returns the gas required to execute the pre-compiled contract.
+func (c *bls12381MapG2) RequiredGas(input []byte) uint64 {
+	return params.Bls12381MapG2Gas
+}
+
+func (c *bls12381MapG2) Run(input []byte) ([]byte, error) {
+	// Implements EIP-2537 Map_FP2_TO_G2 precompile logic.
+	// > Field-to-curve call expects `128` bytes an an input that is interpreted as a an element of the quadratic extension field.
+	// > Output of this call is `256` bytes and is G2 point following respective encoding rules.
+	if len(input) != 128 {
+		return nil, errBLS12381InvalidInputLength
+	}
+
+	// Decode input field element
+	fe := make([]byte, 96)
+	c0, err := decodeBLS12381FieldElement(input[:64])
+	if err != nil {
+		return nil, err
+	}
+	copy(fe[48:], c0)
+	c1, err := decodeBLS12381FieldElement(input[64:])
+	if err != nil {
+		return nil, err
+	}
+	copy(fe[:48], c1)
+
+	// Initialize G2
+	g := bls12381.NewG2()
+
+	// Compute mapping
+	r, err := g.MapToCurve(fe)
+	if err != nil {
+		return nil, err
+	}
+
+	// Encode the G2 point to 256 bytes
+	return g.EncodePoint(r), nil
+}
diff --git a/core/vm/eips.go b/core/vm/eips.go
index 75e5fb1..5ec7587 100644
--- a/core/vm/eips.go
+++ b/core/vm/eips.go
@@ -18,27 +18,44 @@ package vm
 
 import (
 	"fmt"
+	"sort"
 
 	"github.com/ava-labs/coreth/params"
+	"github.com/holiman/uint256"
 )
 
+var activators = map[int]func(*JumpTable){
+	2200: enable2200,
+	1884: enable1884,
+	1344: enable1344,
+	2315: enable2315,
+}
+
 // EnableEIP enables the given EIP on the config.
 // This operation writes in-place, and callers need to ensure that the globally
 // defined jump tables are not polluted.
 func EnableEIP(eipNum int, jt *JumpTable) error {
-	switch eipNum {
-	case 2200:
-		enable2200(jt)
-	case 1884:
-		enable1884(jt)
-	case 1344:
-		enable1344(jt)
-	default:
+	enablerFn, ok := activators[eipNum]
+	if !ok {
 		return fmt.Errorf("undefined eip %d", eipNum)
 	}
+	enablerFn(jt)
 	return nil
 }
 
+func ValidEip(eipNum int) bool {
+	_, ok := activators[eipNum]
+	return ok
+}
+func ActivateableEips() []string {
+	var nums []string
+	for k := range activators {
+		nums = append(nums, fmt.Sprintf("%d", k))
+	}
+	sort.Strings(nums)
+	return nums
+}
+
 // enable1884 applies EIP-1884 to the given jump table:
 // - Increase cost of BALANCE to 700
 // - Increase cost of EXTCODEHASH to 700
@@ -46,23 +63,22 @@ func EnableEIP(eipNum int, jt *JumpTable) error {
 // - Define SELFBALANCE, with cost GasFastStep (5)
 func enable1884(jt *JumpTable) {
 	// Gas cost changes
+	jt[SLOAD].constantGas = params.SloadGasEIP1884
 	jt[BALANCE].constantGas = params.BalanceGasEIP1884
 	jt[EXTCODEHASH].constantGas = params.ExtcodeHashGasEIP1884
-	jt[SLOAD].constantGas = params.SloadGasEIP1884
 
 	// New opcode
-	jt[SELFBALANCE] = operation{
+	jt[SELFBALANCE] = &operation{
 		execute:     opSelfBalance,
 		constantGas: GasFastStep,
 		minStack:    minStack(0, 1),
 		maxStack:    maxStack(0, 1),
-		valid:       true,
 	}
 }
 
-func opSelfBalance(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	balance := interpreter.intPool.get().Set(interpreter.evm.StateDB.GetBalance(contract.Address()))
-	stack.push(balance)
+func opSelfBalance(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	balance, _ := uint256.FromBig(interpreter.evm.StateDB.GetBalance(callContext.contract.Address()))
+	callContext.stack.push(balance)
 	return nil, nil
 }
 
@@ -70,23 +86,51 @@ func opSelfBalance(pc *uint64, interpreter *EVMInterpreter, contract *Contract,
 // - Adds an opcode that returns the current chain’s EIP-155 unique identifier
 func enable1344(jt *JumpTable) {
 	// New opcode
-	jt[CHAINID] = operation{
+	jt[CHAINID] = &operation{
 		execute:     opChainID,
 		constantGas: GasQuickStep,
 		minStack:    minStack(0, 1),
 		maxStack:    maxStack(0, 1),
-		valid:       true,
 	}
 }
 
 // opChainID implements CHAINID opcode
-func opChainID(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	chainId := interpreter.intPool.get().Set(interpreter.evm.chainConfig.ChainID)
-	stack.push(chainId)
+func opChainID(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	chainId, _ := uint256.FromBig(interpreter.evm.chainConfig.ChainID)
+	callContext.stack.push(chainId)
 	return nil, nil
 }
 
 // enable2200 applies EIP-2200 (Rebalance net-metered SSTORE)
 func enable2200(jt *JumpTable) {
+	jt[SLOAD].constantGas = params.SloadGasEIP2200
 	jt[SSTORE].dynamicGas = gasSStoreEIP2200
 }
+
+// enable2315 applies EIP-2315 (Simple Subroutines)
+// - Adds opcodes that jump to and return from subroutines
+func enable2315(jt *JumpTable) {
+	// New opcode
+	jt[BEGINSUB] = &operation{
+		execute:     opBeginSub,
+		constantGas: GasQuickStep,
+		minStack:    minStack(0, 0),
+		maxStack:    maxStack(0, 0),
+	}
+	// New opcode
+	jt[JUMPSUB] = &operation{
+		execute:     opJumpSub,
+		constantGas: GasSlowStep,
+		minStack:    minStack(1, 0),
+		maxStack:    maxStack(1, 0),
+		jumps:       true,
+	}
+	// New opcode
+	jt[RETURNSUB] = &operation{
+		execute:     opReturnSub,
+		constantGas: GasFastStep,
+		minStack:    minStack(0, 0),
+		maxStack:    maxStack(0, 0),
+		jumps:       true,
+	}
+}
diff --git a/core/vm/errors.go b/core/vm/errors.go
index 94f0ed8..9f3f335 100644
--- a/core/vm/errors.go
+++ b/core/vm/errors.go
@@ -16,16 +16,57 @@
 
 package vm
 
-import "errors"
+import (
+	"errors"
+	"fmt"
+)
 
-// List execution errors
+// List evm execution errors
 var (
+	// ErrInvalidSubroutineEntry means that a BEGINSUB was reached via iteration,
+	// as opposed to from a JUMPSUB instruction
+	ErrInvalidSubroutineEntry   = errors.New("invalid subroutine entry")
 	ErrOutOfGas                 = errors.New("out of gas")
 	ErrCodeStoreOutOfGas        = errors.New("contract creation code storage out of gas")
 	ErrDepth                    = errors.New("max call depth exceeded")
-	ErrTraceLimitReached        = errors.New("the number of logs reached the specified limit")
 	ErrInsufficientBalance      = errors.New("insufficient balance for transfer")
 	ErrIncompatibleAccount      = errors.New("incompatible account")
 	ErrContractAddressCollision = errors.New("contract address collision")
-	ErrNoCompatibleInterpreter  = errors.New("no compatible interpreter")
+	ErrExecutionReverted        = errors.New("execution reverted")
+	ErrMaxCodeSizeExceeded      = errors.New("max code size exceeded")
+	ErrInvalidJump              = errors.New("invalid jump destination")
+	ErrWriteProtection          = errors.New("write protection")
+	ErrReturnDataOutOfBounds    = errors.New("return data out of bounds")
+	ErrGasUintOverflow          = errors.New("gas uint64 overflow")
+	ErrInvalidRetsub            = errors.New("invalid retsub")
+	ErrReturnStackExceeded      = errors.New("return stack limit reached")
 )
+
+// ErrStackUnderflow wraps an evm error when the items on the stack less
+// than the minimal requirement.
+type ErrStackUnderflow struct {
+	stackLen int
+	required int
+}
+
+func (e *ErrStackUnderflow) Error() string {
+	return fmt.Sprintf("stack underflow (%d <=> %d)", e.stackLen, e.required)
+}
+
+// ErrStackOverflow wraps an evm error when the items on the stack exceeds
+// the maximum allowance.
+type ErrStackOverflow struct {
+	stackLen int
+	limit    int
+}
+
+func (e *ErrStackOverflow) Error() string {
+	return fmt.Sprintf("stack limit reached %d (%d)", e.stackLen, e.limit)
+}
+
+// ErrInvalidOpCode wraps an evm error when an invalid opcode is encountered.
+type ErrInvalidOpCode struct {
+	opcode OpCode
+}
+
+func (e *ErrInvalidOpCode) Error() string { return fmt.Sprintf("invalid opcode: %s", e.opcode) }
diff --git a/core/vm/evm.go b/core/vm/evm.go
index be8b240..e895211 100644
--- a/core/vm/evm.go
+++ b/core/vm/evm.go
@@ -17,13 +17,15 @@
 package vm
 
 import (
+	"errors"
 	"math/big"
 	"sync/atomic"
 	"time"
 
 	"github.com/ava-labs/coreth/params"
-	"github.com/ava-labs/go-ethereum/common"
-	"github.com/ava-labs/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/holiman/uint256"
 )
 
 // emptyCodeHash is used by create to ensure deployment is disallowed to already
@@ -42,20 +44,24 @@ type (
 	GetHashFunc func(uint64) common.Hash
 )
 
+func (evm *EVM) precompile(addr common.Address) (PrecompiledContract, bool) {
+	var precompiles map[common.Address]PrecompiledContract
+	switch {
+	case evm.chainRules.IsYoloV1:
+		precompiles = PrecompiledContractsYoloV1
+	case evm.chainRules.IsIstanbul:
+		precompiles = PrecompiledContractsIstanbul
+	case evm.chainRules.IsByzantium:
+		precompiles = PrecompiledContractsByzantium
+	default:
+		precompiles = PrecompiledContractsHomestead
+	}
+	p, ok := precompiles[addr]
+	return p, ok
+}
+
 // run runs the given contract and takes care of running precompiles with a fallback to the byte code interpreter.
 func run(evm *EVM, contract *Contract, input []byte, readOnly bool) ([]byte, error) {
-	if contract.CodeAddr != nil {
-		precompiles := PrecompiledContractsHomestead
-		if evm.chainRules.IsByzantium {
-			precompiles = PrecompiledContractsByzantium
-		}
-		if evm.chainRules.IsIstanbul {
-			precompiles = PrecompiledContractsIstanbul
-		}
-		if p := precompiles[*contract.CodeAddr]; p != nil {
-			return RunPrecompiledContract(p, input, contract)
-		}
-	}
 	for _, interpreter := range evm.interpreters {
 		if interpreter.CanRun(contract.Code) {
 			if evm.interpreter != interpreter {
@@ -69,7 +75,7 @@ func run(evm *EVM, contract *Contract, input []byte, readOnly bool) ([]byte, err
 			return interpreter.Run(contract, input, readOnly)
 		}
 	}
-	return nil, ErrNoCompatibleInterpreter
+	return nil, errors.New("no compatible interpreter")
 }
 
 // Context provides the EVM with auxiliary information. Once provided
@@ -194,29 +200,19 @@ func (evm *EVM) Call(caller ContractRef, addr common.Address, input []byte, gas
 	if evm.vmConfig.NoRecursion && evm.depth > 0 {
 		return nil, gas, nil
 	}
-
 	// Fail if we're trying to execute above the call depth limit
 	if evm.depth > int(params.CallCreateDepth) {
 		return nil, gas, ErrDepth
 	}
 	// Fail if we're trying to transfer more than the available balance
-	if !evm.Context.CanTransfer(evm.StateDB, caller.Address(), value) {
+	if value.Sign() != 0 && !evm.Context.CanTransfer(evm.StateDB, caller.Address(), value) {
 		return nil, gas, ErrInsufficientBalance
 	}
+	snapshot := evm.StateDB.Snapshot()
+	p, isPrecompile := evm.precompile(addr)
 
-	var (
-		to       = AccountRef(addr)
-		snapshot = evm.StateDB.Snapshot()
-	)
 	if !evm.StateDB.Exist(addr) {
-		precompiles := PrecompiledContractsHomestead
-		if evm.chainRules.IsByzantium {
-			precompiles = PrecompiledContractsByzantium
-		}
-		if evm.chainRules.IsIstanbul {
-			precompiles = PrecompiledContractsIstanbul
-		}
-		if precompiles[addr] == nil && evm.chainRules.IsEIP158 && value.Sign() == 0 {
+		if !isPrecompile && evm.chainRules.IsEIP158 && value.Sign() == 0 {
 			// Calling a non existing account, don't do anything, but ping the tracer
 			if evm.vmConfig.Debug && evm.depth == 0 {
 				evm.vmConfig.Tracer.CaptureStart(caller.Address(), addr, false, input, gas, value)
@@ -226,35 +222,47 @@ func (evm *EVM) Call(caller ContractRef, addr common.Address, input []byte, gas
 		}
 		evm.StateDB.CreateAccount(addr)
 	}
-	evm.Transfer(evm.StateDB, caller.Address(), to.Address(), value)
-	// Initialise a new contract and set the code that is to be used by the EVM.
-	// The contract is a scoped environment for this execution context only.
-	contract := NewContract(caller, to, value, gas)
-	contract.SetCallCode(&addr, evm.StateDB.GetCodeHash(addr), evm.StateDB.GetCode(addr))
-
-	// Even if the account has no code, we need to continue because it might be a precompile
-	start := time.Now()
+	evm.Transfer(evm.StateDB, caller.Address(), addr, value)
 
 	// Capture the tracer start/end events in debug mode
 	if evm.vmConfig.Debug && evm.depth == 0 {
 		evm.vmConfig.Tracer.CaptureStart(caller.Address(), addr, false, input, gas, value)
-
-		defer func() { // Lazy evaluation of the parameters
-			evm.vmConfig.Tracer.CaptureEnd(ret, gas-contract.Gas, time.Since(start), err)
-		}()
+		defer func(startGas uint64, startTime time.Time) { // Lazy evaluation of the parameters
+			evm.vmConfig.Tracer.CaptureEnd(ret, startGas-gas, time.Since(startTime), err)
+		}(gas, time.Now())
+	}
+
+	if isPrecompile {
+		ret, gas, err = RunPrecompiledContract(p, input, gas)
+	} else {
+		// Initialise a new contract and set the code that is to be used by the EVM.
+		// The contract is a scoped environment for this execution context only.
+		code := evm.StateDB.GetCode(addr)
+		if len(code) == 0 {
+			ret, err = nil, nil // gas is unchanged
+		} else {
+			addrCopy := addr
+			// If the account has no code, we can abort here
+			// The depth-check is already done, and precompiles handled above
+			contract := NewContract(caller, AccountRef(addrCopy), value, gas)
+			contract.SetCallCode(&addrCopy, evm.StateDB.GetCodeHash(addrCopy), code)
+			ret, err = run(evm, contract, input, false)
+			gas = contract.Gas
+		}
 	}
-	ret, err = run(evm, contract, input, false)
-
 	// When an error was returned by the EVM or when setting the creation code
 	// above we revert to the snapshot and consume any gas remaining. Additionally
 	// when we're in homestead this also counts for code storage gas errors.
 	if err != nil {
 		evm.StateDB.RevertToSnapshot(snapshot)
-		if err != errExecutionReverted {
-			contract.UseGas(contract.Gas)
+		if err != ErrExecutionReverted {
+			gas = 0
 		}
+		// TODO: consider clearing up unused snapshots:
+		//} else {
+		//	evm.StateDB.DiscardSnapshot(snapshot)
 	}
-	return ret, contract.Gas, err
+	return ret, gas, err
 }
 
 // This allows the user transfer balance of a specified coinId in addition to a normal Call().
@@ -262,13 +270,13 @@ func (evm *EVM) CallExpert(caller ContractRef, addr common.Address, input []byte
 	if evm.vmConfig.NoRecursion && evm.depth > 0 {
 		return nil, gas, nil
 	}
-
 	// Fail if we're trying to execute above the call depth limit
 	if evm.depth > int(params.CallCreateDepth) {
 		return nil, gas, ErrDepth
 	}
+
 	// Fail if we're trying to transfer more than the available balance
-	if !evm.Context.CanTransfer(evm.StateDB, caller.Address(), value) {
+	if value.Sign() != 0 && !evm.Context.CanTransfer(evm.StateDB, caller.Address(), value) {
 		return nil, gas, ErrInsufficientBalance
 	}
 
@@ -280,17 +288,11 @@ func (evm *EVM) CallExpert(caller ContractRef, addr common.Address, input []byte
 		return nil, gas, ErrIncompatibleAccount
 	}
 
-	var snapshot = evm.StateDB.Snapshot()
+	snapshot := evm.StateDB.Snapshot()
+	p, isPrecompile := evm.precompile(addr)
 
 	if !evm.StateDB.Exist(addr) {
-		precompiles := PrecompiledContractsHomestead
-		if evm.chainRules.IsByzantium {
-			precompiles = PrecompiledContractsByzantium
-		}
-		if evm.chainRules.IsIstanbul {
-			precompiles = PrecompiledContractsIstanbul
-		}
-		if precompiles[addr] == nil && evm.chainRules.IsEIP158 && value.Sign() == 0 {
+		if !isPrecompile && evm.chainRules.IsEIP158 && value.Sign() == 0 {
 			// Calling a non existing account, don't do anything, but ping the tracer
 			if evm.vmConfig.Debug && evm.depth == 0 {
 				evm.vmConfig.Tracer.CaptureStart(caller.Address(), addr, false, input, gas, value)
@@ -300,36 +302,48 @@ func (evm *EVM) CallExpert(caller ContractRef, addr common.Address, input []byte
 		}
 		evm.StateDB.CreateAccount(addr)
 	}
-	evm.Transfer(evm.StateDB, caller.Address(), to.Address(), value)
-	evm.TransferMultiCoin(evm.StateDB, caller.Address(), to.Address(), coinID, value2)
-	// Initialise a new contract and set the code that is to be used by the EVM.
-	// The contract is a scoped environment for this execution context only.
-	contract := NewContract(caller, to, value, gas)
-	contract.SetCallCode(&addr, evm.StateDB.GetCodeHash(addr), evm.StateDB.GetCode(addr))
-
-	// Even if the account has no code, we need to continue because it might be a precompile
-	start := time.Now()
+	evm.Transfer(evm.StateDB, caller.Address(), addr, value)
+	evm.TransferMultiCoin(evm.StateDB, caller.Address(), addr, coinID, value2)
 
 	// Capture the tracer start/end events in debug mode
 	if evm.vmConfig.Debug && evm.depth == 0 {
 		evm.vmConfig.Tracer.CaptureStart(caller.Address(), addr, false, input, gas, value)
-
-		defer func() { // Lazy evaluation of the parameters
-			evm.vmConfig.Tracer.CaptureEnd(ret, gas-contract.Gas, time.Since(start), err)
-		}()
+		defer func(startGas uint64, startTime time.Time) { // Lazy evaluation of the parameters
+			evm.vmConfig.Tracer.CaptureEnd(ret, startGas-gas, time.Since(startTime), err)
+		}(gas, time.Now())
+	}
+
+	if isPrecompile {
+		ret, gas, err = RunPrecompiledContract(p, input, gas)
+	} else {
+		// Initialise a new contract and set the code that is to be used by the EVM.
+		// The contract is a scoped environment for this execution context only.
+		code := evm.StateDB.GetCode(addr)
+		if len(code) == 0 {
+			ret, err = nil, nil // gas is unchanged
+		} else {
+			addrCopy := addr
+			// If the account has no code, we can abort here
+			// The depth-check is already done, and precompiles handled above
+			contract := NewContract(caller, AccountRef(addrCopy), value, gas)
+			contract.SetCallCode(&addrCopy, evm.StateDB.GetCodeHash(addrCopy), code)
+			ret, err = run(evm, contract, input, false)
+			gas = contract.Gas
+		}
 	}
-	ret, err = run(evm, contract, input, false)
-
 	// When an error was returned by the EVM or when setting the creation code
 	// above we revert to the snapshot and consume any gas remaining. Additionally
 	// when we're in homestead this also counts for code storage gas errors.
 	if err != nil {
 		evm.StateDB.RevertToSnapshot(snapshot)
-		if err != errExecutionReverted {
-			contract.UseGas(contract.Gas)
+		if err != ErrExecutionReverted {
+			gas = 0
 		}
+		// TODO: consider clearing up unused snapshots:
+		//} else {
+		//	evm.StateDB.DiscardSnapshot(snapshot)
 	}
-	return ret, contract.Gas, err
+	return ret, gas, err
 }
 
 // CallCode executes the contract associated with the addr with the given input
@@ -343,33 +357,38 @@ func (evm *EVM) CallCode(caller ContractRef, addr common.Address, input []byte,
 	if evm.vmConfig.NoRecursion && evm.depth > 0 {
 		return nil, gas, nil
 	}
-
 	// Fail if we're trying to execute above the call depth limit
 	if evm.depth > int(params.CallCreateDepth) {
 		return nil, gas, ErrDepth
 	}
 	// Fail if we're trying to transfer more than the available balance
-	if !evm.CanTransfer(evm.StateDB, caller.Address(), value) {
+	// Note although it's noop to transfer X ether to caller itself. But
+	// if caller doesn't have enough balance, it would be an error to allow
+	// over-charging itself. So the check here is necessary.
+	if !evm.Context.CanTransfer(evm.StateDB, caller.Address(), value) {
 		return nil, gas, ErrInsufficientBalance
 	}
+	var snapshot = evm.StateDB.Snapshot()
 
-	var (
-		snapshot = evm.StateDB.Snapshot()
-		to       = AccountRef(caller.Address())
-	)
-	// Initialise a new contract and set the code that is to be used by the EVM.
-	// The contract is a scoped environment for this execution context only.
-	contract := NewContract(caller, to, value, gas)
-	contract.SetCallCode(&addr, evm.StateDB.GetCodeHash(addr), evm.StateDB.GetCode(addr))
-
-	ret, err = run(evm, contract, input, false)
+	// It is allowed to call precompiles, even via delegatecall
+	if p, isPrecompile := evm.precompile(addr); isPrecompile {
+		ret, gas, err = RunPrecompiledContract(p, input, gas)
+	} else {
+		addrCopy := addr
+		// Initialise a new contract and set the code that is to be used by the EVM.
+		// The contract is a scoped environment for this execution context only.
+		contract := NewContract(caller, AccountRef(caller.Address()), value, gas)
+		contract.SetCallCode(&addrCopy, evm.StateDB.GetCodeHash(addrCopy), evm.StateDB.GetCode(addrCopy))
+		ret, err = run(evm, contract, input, false)
+		gas = contract.Gas
+	}
 	if err != nil {
 		evm.StateDB.RevertToSnapshot(snapshot)
-		if err != errExecutionReverted {
-			contract.UseGas(contract.Gas)
+		if err != ErrExecutionReverted {
+			gas = 0
 		}
 	}
-	return ret, contract.Gas, err
+	return ret, gas, err
 }
 
 // DelegateCall executes the contract associated with the addr with the given input
@@ -385,24 +404,26 @@ func (evm *EVM) DelegateCall(caller ContractRef, addr common.Address, input []by
 	if evm.depth > int(params.CallCreateDepth) {
 		return nil, gas, ErrDepth
 	}
+	var snapshot = evm.StateDB.Snapshot()
 
-	var (
-		snapshot = evm.StateDB.Snapshot()
-		to       = AccountRef(caller.Address())
-	)
-
-	// Initialise a new contract and make initialise the delegate values
-	contract := NewContract(caller, to, nil, gas).AsDelegate()
-	contract.SetCallCode(&addr, evm.StateDB.GetCodeHash(addr), evm.StateDB.GetCode(addr))
-
-	ret, err = run(evm, contract, input, false)
+	// It is allowed to call precompiles, even via delegatecall
+	if p, isPrecompile := evm.precompile(addr); isPrecompile {
+		ret, gas, err = RunPrecompiledContract(p, input, gas)
+	} else {
+		addrCopy := addr
+		// Initialise a new contract and make initialise the delegate values
+		contract := NewContract(caller, AccountRef(caller.Address()), nil, gas).AsDelegate()
+		contract.SetCallCode(&addrCopy, evm.StateDB.GetCodeHash(addrCopy), evm.StateDB.GetCode(addrCopy))
+		ret, err = run(evm, contract, input, false)
+		gas = contract.Gas
+	}
 	if err != nil {
 		evm.StateDB.RevertToSnapshot(snapshot)
-		if err != errExecutionReverted {
-			contract.UseGas(contract.Gas)
+		if err != ErrExecutionReverted {
+			gas = 0
 		}
 	}
-	return ret, contract.Gas, err
+	return ret, gas, err
 }
 
 // StaticCall executes the contract associated with the addr with the given input
@@ -417,33 +438,43 @@ func (evm *EVM) StaticCall(caller ContractRef, addr common.Address, input []byte
 	if evm.depth > int(params.CallCreateDepth) {
 		return nil, gas, ErrDepth
 	}
-
-	var (
-		to       = AccountRef(addr)
-		snapshot = evm.StateDB.Snapshot()
-	)
-	// Initialise a new contract and set the code that is to be used by the EVM.
-	// The contract is a scoped environment for this execution context only.
-	contract := NewContract(caller, to, new(big.Int), gas)
-	contract.SetCallCode(&addr, evm.StateDB.GetCodeHash(addr), evm.StateDB.GetCode(addr))
+	// We take a snapshot here. This is a bit counter-intuitive, and could probably be skipped.
+	// However, even a staticcall is considered a 'touch'. On mainnet, static calls were introduced
+	// after all empty accounts were deleted, so this is not required. However, if we omit this,
+	// then certain tests start failing; stRevertTest/RevertPrecompiledTouchExactOOG.json.
+	// We could change this, but for now it's left for legacy reasons
+	var snapshot = evm.StateDB.Snapshot()
 
 	// We do an AddBalance of zero here, just in order to trigger a touch.
 	// This doesn't matter on Mainnet, where all empties are gone at the time of Byzantium,
 	// but is the correct thing to do and matters on other networks, in tests, and potential
 	// future scenarios
-	evm.StateDB.AddBalance(addr, bigZero)
-
-	// When an error was returned by the EVM or when setting the creation code
-	// above we revert to the snapshot and consume any gas remaining. Additionally
-	// when we're in Homestead this also counts for code storage gas errors.
-	ret, err = run(evm, contract, input, true)
+	evm.StateDB.AddBalance(addr, big0)
+
+	if p, isPrecompile := evm.precompile(addr); isPrecompile {
+		ret, gas, err = RunPrecompiledContract(p, input, gas)
+	} else {
+		// At this point, we use a copy of address. If we don't, the go compiler will
+		// leak the 'contract' to the outer scope, and make allocation for 'contract'
+		// even if the actual execution ends on RunPrecompiled above.
+		addrCopy := addr
+		// Initialise a new contract and set the code that is to be used by the EVM.
+		// The contract is a scoped environment for this execution context only.
+		contract := NewContract(caller, AccountRef(addrCopy), new(big.Int), gas)
+		contract.SetCallCode(&addrCopy, evm.StateDB.GetCodeHash(addrCopy), evm.StateDB.GetCode(addrCopy))
+		// When an error was returned by the EVM or when setting the creation code
+		// above we revert to the snapshot and consume any gas remaining. Additionally
+		// when we're in Homestead this also counts for code storage gas errors.
+		ret, err = run(evm, contract, input, true)
+		gas = contract.Gas
+	}
 	if err != nil {
 		evm.StateDB.RevertToSnapshot(snapshot)
-		if err != errExecutionReverted {
-			contract.UseGas(contract.Gas)
+		if err != ErrExecutionReverted {
+			gas = 0
 		}
 	}
-	return ret, contract.Gas, err
+	return ret, gas, err
 }
 
 type codeAndHash struct {
@@ -520,13 +551,13 @@ func (evm *EVM) create(caller ContractRef, codeAndHash *codeAndHash, gas uint64,
 	// when we're in homestead this also counts for code storage gas errors.
 	if maxCodeSizeExceeded || (err != nil && (evm.chainRules.IsHomestead || err != ErrCodeStoreOutOfGas)) {
 		evm.StateDB.RevertToSnapshot(snapshot)
-		if err != errExecutionReverted {
+		if err != ErrExecutionReverted {
 			contract.UseGas(contract.Gas)
 		}
 	}
 	// Assign err if contract code size exceeds the max while the err is still empty.
 	if maxCodeSizeExceeded && err == nil {
-		err = errMaxCodeSizeExceeded
+		err = ErrMaxCodeSizeExceeded
 	}
 	if evm.vmConfig.Debug && evm.depth == 0 {
 		evm.vmConfig.Tracer.CaptureEnd(ret, gas-contract.Gas, time.Since(start), err)
@@ -545,9 +576,9 @@ func (evm *EVM) Create(caller ContractRef, code []byte, gas uint64, value *big.I
 //
 // The different between Create2 with Create is Create2 uses sha3(0xff ++ msg.sender ++ salt ++ sha3(init_code))[12:]
 // instead of the usual sender-and-nonce-hash as the address where the contract is initialized at.
-func (evm *EVM) Create2(caller ContractRef, code []byte, gas uint64, endowment *big.Int, salt *big.Int) (ret []byte, contractAddr common.Address, leftOverGas uint64, err error) {
+func (evm *EVM) Create2(caller ContractRef, code []byte, gas uint64, endowment *big.Int, salt *uint256.Int) (ret []byte, contractAddr common.Address, leftOverGas uint64, err error) {
 	codeAndHash := &codeAndHash{code: code}
-	contractAddr = crypto.CreateAddress2(caller.Address(), common.BigToHash(salt), codeAndHash.Hash().Bytes())
+	contractAddr = crypto.CreateAddress2(caller.Address(), common.Hash(salt.Bytes32()), codeAndHash.Hash().Bytes())
 	return evm.create(caller, codeAndHash, gas, endowment, contractAddr)
 }
 
diff --git a/core/vm/gas.go b/core/vm/gas.go
index bd8b4f1..5cf1d85 100644
--- a/core/vm/gas.go
+++ b/core/vm/gas.go
@@ -17,7 +17,7 @@
 package vm
 
 import (
-	"math/big"
+	"github.com/holiman/uint256"
 )
 
 // Gas costs
@@ -30,23 +30,23 @@ const (
 	GasExtStep     uint64 = 20
 )
 
-// calcGas returns the actual gas cost of the call.
+// callGas returns the actual gas cost of the call.
 //
 // The cost of gas was changed during the homestead price change HF.
 // As part of EIP 150 (TangerineWhistle), the returned gas is gas - base * 63 / 64.
-func callGas(isEip150 bool, availableGas, base uint64, callCost *big.Int) (uint64, error) {
+func callGas(isEip150 bool, availableGas, base uint64, callCost *uint256.Int) (uint64, error) {
 	if isEip150 {
 		availableGas = availableGas - base
 		gas := availableGas - availableGas/64
 		// If the bit length exceeds 64 bit we know that the newly calculated "gas" for EIP150
-		// is smaller than the requested amount. Therefor we return the new gas instead
+		// is smaller than the requested amount. Therefore we return the new gas instead
 		// of returning an error.
 		if !callCost.IsUint64() || gas < callCost.Uint64() {
 			return gas, nil
 		}
 	}
 	if !callCost.IsUint64() {
-		return 0, errGasUintOverflow
+		return 0, ErrGasUintOverflow
 	}
 
 	return callCost.Uint64(), nil
diff --git a/core/vm/gas_table.go b/core/vm/gas_table.go
index 2adaf85..0182892 100644
--- a/core/vm/gas_table.go
+++ b/core/vm/gas_table.go
@@ -20,8 +20,8 @@ import (
 	"errors"
 
 	"github.com/ava-labs/coreth/params"
-	"github.com/ava-labs/go-ethereum/common"
-	"github.com/ava-labs/go-ethereum/common/math"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/math"
 )
 
 // memoryGasCost calculates the quadratic gas for memory expansion. It does so
@@ -36,7 +36,7 @@ func memoryGasCost(mem *Memory, newMemSize uint64) (uint64, error) {
 	// overflow. The constant 0x1FFFFFFFE0 is the highest number that can be used
 	// without overflowing the gas calculation.
 	if newMemSize > 0x1FFFFFFFE0 {
-		return 0, errGasUintOverflow
+		return 0, ErrGasUintOverflow
 	}
 	newMemSizeWords := toWordSize(newMemSize)
 	newMemSize = newMemSizeWords * 32
@@ -70,17 +70,17 @@ func memoryCopierGas(stackpos int) gasFunc {
 			return 0, err
 		}
 		// And gas for copying data, charged per word at param.CopyGas
-		words, overflow := bigUint64(stack.Back(stackpos))
+		words, overflow := stack.Back(stackpos).Uint64WithOverflow()
 		if overflow {
-			return 0, errGasUintOverflow
+			return 0, ErrGasUintOverflow
 		}
 
 		if words, overflow = math.SafeMul(toWordSize(words), params.CopyGas); overflow {
-			return 0, errGasUintOverflow
+			return 0, ErrGasUintOverflow
 		}
 
 		if gas, overflow = math.SafeAdd(gas, words); overflow {
-			return 0, errGasUintOverflow
+			return 0, ErrGasUintOverflow
 		}
 		return gas, nil
 	}
@@ -96,7 +96,7 @@ var (
 func gasSStore(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
 	var (
 		y, x    = stack.Back(1), stack.Back(0)
-		current = evm.StateDB.GetState(contract.Address(), common.BigToHash(x))
+		current = evm.StateDB.GetState(contract.Address(), common.Hash(x.Bytes32()))
 	)
 	// The legacy gas metering only takes into consideration the current state
 	// Legacy rules should be applied if we are in Petersburg (removal of EIP-1283)
@@ -131,11 +131,11 @@ func gasSStore(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySi
 	// 	  2.2.2. If original value equals new value (this storage slot is reset)
 	//       2.2.2.1. If original value is 0, add 19800 gas to refund counter.
 	// 	     2.2.2.2. Otherwise, add 4800 gas to refund counter.
-	value := common.BigToHash(y)
+	value := common.Hash(y.Bytes32())
 	if current == value { // noop (1)
 		return params.NetSstoreNoopGas, nil
 	}
-	original := evm.StateDB.GetCommittedState(contract.Address(), common.BigToHash(x))
+	original := evm.StateDB.GetCommittedState(contract.Address(), common.Hash(x.Bytes32()))
 	if original == current {
 		if original == (common.Hash{}) { // create slot (2.1.1)
 			return params.NetSstoreInitGas, nil
@@ -183,14 +183,14 @@ func gasSStoreEIP2200(evm *EVM, contract *Contract, stack *Stack, mem *Memory, m
 	// Gas sentry honoured, do the actual gas calculation based on the stored value
 	var (
 		y, x    = stack.Back(1), stack.Back(0)
-		current = evm.StateDB.GetState(contract.Address(), common.BigToHash(x))
+		current = evm.StateDB.GetState(contract.Address(), common.Hash(x.Bytes32()))
 	)
-	value := common.BigToHash(y)
+	value := common.Hash(y.Bytes32())
 
 	if current == value { // noop (1)
 		return params.SstoreNoopGasEIP2200, nil
 	}
-	original := evm.StateDB.GetCommittedState(contract.Address(), common.BigToHash(x))
+	original := evm.StateDB.GetCommittedState(contract.Address(), common.Hash(x.Bytes32()))
 	if original == current {
 		if original == (common.Hash{}) { // create slot (2.1.1)
 			return params.SstoreInitGasEIP2200, nil
@@ -219,9 +219,9 @@ func gasSStoreEIP2200(evm *EVM, contract *Contract, stack *Stack, mem *Memory, m
 
 func makeGasLog(n uint64) gasFunc {
 	return func(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
-		requestedSize, overflow := bigUint64(stack.Back(1))
+		requestedSize, overflow := stack.Back(1).Uint64WithOverflow()
 		if overflow {
-			return 0, errGasUintOverflow
+			return 0, ErrGasUintOverflow
 		}
 
 		gas, err := memoryGasCost(mem, memorySize)
@@ -230,18 +230,18 @@ func makeGasLog(n uint64) gasFunc {
 		}
 
 		if gas, overflow = math.SafeAdd(gas, params.LogGas); overflow {
-			return 0, errGasUintOverflow
+			return 0, ErrGasUintOverflow
 		}
 		if gas, overflow = math.SafeAdd(gas, n*params.LogTopicGas); overflow {
-			return 0, errGasUintOverflow
+			return 0, ErrGasUintOverflow
 		}
 
 		var memorySizeGas uint64
 		if memorySizeGas, overflow = math.SafeMul(requestedSize, params.LogDataGas); overflow {
-			return 0, errGasUintOverflow
+			return 0, ErrGasUintOverflow
 		}
 		if gas, overflow = math.SafeAdd(gas, memorySizeGas); overflow {
-			return 0, errGasUintOverflow
+			return 0, ErrGasUintOverflow
 		}
 		return gas, nil
 	}
@@ -252,15 +252,15 @@ func gasSha3(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize
 	if err != nil {
 		return 0, err
 	}
-	wordGas, overflow := bigUint64(stack.Back(1))
+	wordGas, overflow := stack.Back(1).Uint64WithOverflow()
 	if overflow {
-		return 0, errGasUintOverflow
+		return 0, ErrGasUintOverflow
 	}
 	if wordGas, overflow = math.SafeMul(toWordSize(wordGas), params.Sha3WordGas); overflow {
-		return 0, errGasUintOverflow
+		return 0, ErrGasUintOverflow
 	}
 	if gas, overflow = math.SafeAdd(gas, wordGas); overflow {
-		return 0, errGasUintOverflow
+		return 0, ErrGasUintOverflow
 	}
 	return gas, nil
 }
@@ -286,15 +286,15 @@ func gasCreate2(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memoryS
 	if err != nil {
 		return 0, err
 	}
-	wordGas, overflow := bigUint64(stack.Back(2))
+	wordGas, overflow := stack.Back(2).Uint64WithOverflow()
 	if overflow {
-		return 0, errGasUintOverflow
+		return 0, ErrGasUintOverflow
 	}
 	if wordGas, overflow = math.SafeMul(toWordSize(wordGas), params.Sha3WordGas); overflow {
-		return 0, errGasUintOverflow
+		return 0, ErrGasUintOverflow
 	}
 	if gas, overflow = math.SafeAdd(gas, wordGas); overflow {
-		return 0, errGasUintOverflow
+		return 0, ErrGasUintOverflow
 	}
 	return gas, nil
 }
@@ -307,7 +307,7 @@ func gasExpFrontier(evm *EVM, contract *Contract, stack *Stack, mem *Memory, mem
 		overflow bool
 	)
 	if gas, overflow = math.SafeAdd(gas, params.ExpGas); overflow {
-		return 0, errGasUintOverflow
+		return 0, ErrGasUintOverflow
 	}
 	return gas, nil
 }
@@ -320,7 +320,7 @@ func gasExpEIP158(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memor
 		overflow bool
 	)
 	if gas, overflow = math.SafeAdd(gas, params.ExpGas); overflow {
-		return 0, errGasUintOverflow
+		return 0, ErrGasUintOverflow
 	}
 	return gas, nil
 }
@@ -328,8 +328,8 @@ func gasExpEIP158(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memor
 func gasCall(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
 	var (
 		gas            uint64
-		transfersValue = stack.Back(2).Sign() != 0
-		address        = common.BigToAddress(stack.Back(1))
+		transfersValue = !stack.Back(2).IsZero()
+		address        = common.Address(stack.Back(1).Bytes20())
 	)
 	if evm.chainRules.IsEIP158 {
 		if transfersValue && evm.StateDB.Empty(address) {
@@ -347,7 +347,7 @@ func gasCall(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize
 	}
 	var overflow bool
 	if gas, overflow = math.SafeAdd(gas, memoryGas); overflow {
-		return 0, errGasUintOverflow
+		return 0, ErrGasUintOverflow
 	}
 
 	evm.callGasTemp, err = callGas(evm.chainRules.IsEIP150, contract.Gas, gas, stack.Back(0))
@@ -355,7 +355,7 @@ func gasCall(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize
 		return 0, err
 	}
 	if gas, overflow = math.SafeAdd(gas, evm.callGasTemp); overflow {
-		return 0, errGasUintOverflow
+		return 0, ErrGasUintOverflow
 	}
 	return gas, nil
 }
@@ -373,14 +373,14 @@ func gasCallCode(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memory
 		gas += params.CallValueTransferGas
 	}
 	if gas, overflow = math.SafeAdd(gas, memoryGas); overflow {
-		return 0, errGasUintOverflow
+		return 0, ErrGasUintOverflow
 	}
 	evm.callGasTemp, err = callGas(evm.chainRules.IsEIP150, contract.Gas, gas, stack.Back(0))
 	if err != nil {
 		return 0, err
 	}
 	if gas, overflow = math.SafeAdd(gas, evm.callGasTemp); overflow {
-		return 0, errGasUintOverflow
+		return 0, ErrGasUintOverflow
 	}
 	return gas, nil
 }
@@ -396,7 +396,7 @@ func gasDelegateCall(evm *EVM, contract *Contract, stack *Stack, mem *Memory, me
 	}
 	var overflow bool
 	if gas, overflow = math.SafeAdd(gas, evm.callGasTemp); overflow {
-		return 0, errGasUintOverflow
+		return 0, ErrGasUintOverflow
 	}
 	return gas, nil
 }
@@ -412,7 +412,7 @@ func gasStaticCall(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memo
 	}
 	var overflow bool
 	if gas, overflow = math.SafeAdd(gas, evm.callGasTemp); overflow {
-		return 0, errGasUintOverflow
+		return 0, ErrGasUintOverflow
 	}
 	return gas, nil
 }
@@ -422,7 +422,7 @@ func gasSelfdestruct(evm *EVM, contract *Contract, stack *Stack, mem *Memory, me
 	// EIP150 homestead gas reprice fork:
 	if evm.chainRules.IsEIP150 {
 		gas = params.SelfdestructGasEIP150
-		var address = common.BigToAddress(stack.Back(0))
+		var address = common.Address(stack.Back(0).Bytes20())
 
 		if evm.chainRules.IsEIP158 {
 			// if empty and transfers value
diff --git a/core/vm/gen_structlog.go b/core/vm/gen_structlog.go
index 038841c..ac1a907 100644
--- a/core/vm/gen_structlog.go
+++ b/core/vm/gen_structlog.go
@@ -6,9 +6,9 @@ import (
 	"encoding/json"
 	"math/big"
 
-	"github.com/ava-labs/go-ethereum/common"
-	"github.com/ava-labs/go-ethereum/common/hexutil"
-	"github.com/ava-labs/go-ethereum/common/math"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/common/math"
 )
 
 var _ = (*structLogMarshaling)(nil)
@@ -23,6 +23,8 @@ func (s StructLog) MarshalJSON() ([]byte, error) {
 		Memory        hexutil.Bytes               `json:"memory"`
 		MemorySize    int                         `json:"memSize"`
 		Stack         []*math.HexOrDecimal256     `json:"stack"`
+		ReturnStack   []math.HexOrDecimal64       `json:"returnStack"`
+		ReturnData    []byte                      `json:"returnData"`
 		Storage       map[common.Hash]common.Hash `json:"-"`
 		Depth         int                         `json:"depth"`
 		RefundCounter uint64                      `json:"refund"`
@@ -43,6 +45,13 @@ func (s StructLog) MarshalJSON() ([]byte, error) {
 			enc.Stack[k] = (*math.HexOrDecimal256)(v)
 		}
 	}
+	if s.ReturnStack != nil {
+		enc.ReturnStack = make([]math.HexOrDecimal64, len(s.ReturnStack))
+		for k, v := range s.ReturnStack {
+			enc.ReturnStack[k] = math.HexOrDecimal64(v)
+		}
+	}
+	enc.ReturnData = s.ReturnData
 	enc.Storage = s.Storage
 	enc.Depth = s.Depth
 	enc.RefundCounter = s.RefundCounter
@@ -62,6 +71,8 @@ func (s *StructLog) UnmarshalJSON(input []byte) error {
 		Memory        *hexutil.Bytes              `json:"memory"`
 		MemorySize    *int                        `json:"memSize"`
 		Stack         []*math.HexOrDecimal256     `json:"stack"`
+		ReturnStack   []math.HexOrDecimal64       `json:"returnStack"`
+		ReturnData    []byte                      `json:"returnData"`
 		Storage       map[common.Hash]common.Hash `json:"-"`
 		Depth         *int                        `json:"depth"`
 		RefundCounter *uint64                     `json:"refund"`
@@ -95,6 +106,15 @@ func (s *StructLog) UnmarshalJSON(input []byte) error {
 			s.Stack[k] = (*big.Int)(v)
 		}
 	}
+	if dec.ReturnStack != nil {
+		s.ReturnStack = make([]uint32, len(dec.ReturnStack))
+		for k, v := range dec.ReturnStack {
+			s.ReturnStack[k] = uint32(v)
+		}
+	}
+	if dec.ReturnData != nil {
+		s.ReturnData = dec.ReturnData
+	}
 	if dec.Storage != nil {
 		s.Storage = dec.Storage
 	}
diff --git a/core/vm/instructions.go b/core/vm/instructions.go
index ecdccbd..abfa2aa 100644
--- a/core/vm/instructions.go
+++ b/core/vm/instructions.go
@@ -18,373 +18,223 @@ package vm
 
 import (
 	"errors"
-	"math/big"
-
 	"github.com/ava-labs/coreth/core/types"
 	"github.com/ava-labs/coreth/params"
-	"github.com/ava-labs/go-ethereum/common"
-	"github.com/ava-labs/go-ethereum/common/math"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/holiman/uint256"
 	"golang.org/x/crypto/sha3"
 )
 
-var (
-	bigZero                  = new(big.Int)
-	tt255                    = math.BigPow(2, 255)
-	errWriteProtection       = errors.New("evm: write protection")
-	errReturnDataOutOfBounds = errors.New("evm: return data out of bounds")
-	errExecutionReverted     = errors.New("evm: execution reverted")
-	errMaxCodeSizeExceeded   = errors.New("evm: max code size exceeded")
-	errInvalidJump           = errors.New("evm: invalid jump destination")
-)
-
-func opAdd(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	x, y := stack.pop(), stack.peek()
-	math.U256(y.Add(x, y))
-
-	interpreter.intPool.put(x)
+func opAdd(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	x, y := callContext.stack.pop(), callContext.stack.peek()
+	y.Add(&x, y)
 	return nil, nil
 }
 
-func opSub(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	x, y := stack.pop(), stack.peek()
-	math.U256(y.Sub(x, y))
-
-	interpreter.intPool.put(x)
+func opSub(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	x, y := callContext.stack.pop(), callContext.stack.peek()
+	y.Sub(&x, y)
 	return nil, nil
 }
 
-func opMul(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	x, y := stack.pop(), stack.pop()
-	stack.push(math.U256(x.Mul(x, y)))
-
-	interpreter.intPool.put(y)
-
+func opMul(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	x, y := callContext.stack.pop(), callContext.stack.peek()
+	y.Mul(&x, y)
 	return nil, nil
 }
 
-func opDiv(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	x, y := stack.pop(), stack.peek()
-	if y.Sign() != 0 {
-		math.U256(y.Div(x, y))
-	} else {
-		y.SetUint64(0)
-	}
-	interpreter.intPool.put(x)
+func opDiv(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	x, y := callContext.stack.pop(), callContext.stack.peek()
+	y.Div(&x, y)
 	return nil, nil
 }
 
-func opSdiv(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	x, y := math.S256(stack.pop()), math.S256(stack.pop())
-	res := interpreter.intPool.getZero()
-
-	if y.Sign() == 0 || x.Sign() == 0 {
-		stack.push(res)
-	} else {
-		if x.Sign() != y.Sign() {
-			res.Div(x.Abs(x), y.Abs(y))
-			res.Neg(res)
-		} else {
-			res.Div(x.Abs(x), y.Abs(y))
-		}
-		stack.push(math.U256(res))
-	}
-	interpreter.intPool.put(x, y)
+func opSdiv(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	x, y := callContext.stack.pop(), callContext.stack.peek()
+	y.SDiv(&x, y)
 	return nil, nil
 }
 
-func opMod(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	x, y := stack.pop(), stack.pop()
-	if y.Sign() == 0 {
-		stack.push(x.SetUint64(0))
-	} else {
-		stack.push(math.U256(x.Mod(x, y)))
-	}
-	interpreter.intPool.put(y)
+func opMod(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	x, y := callContext.stack.pop(), callContext.stack.peek()
+	y.Mod(&x, y)
 	return nil, nil
 }
 
-func opSmod(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	x, y := math.S256(stack.pop()), math.S256(stack.pop())
-	res := interpreter.intPool.getZero()
-
-	if y.Sign() == 0 {
-		stack.push(res)
-	} else {
-		if x.Sign() < 0 {
-			res.Mod(x.Abs(x), y.Abs(y))
-			res.Neg(res)
-		} else {
-			res.Mod(x.Abs(x), y.Abs(y))
-		}
-		stack.push(math.U256(res))
-	}
-	interpreter.intPool.put(x, y)
+func opSmod(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	x, y := callContext.stack.pop(), callContext.stack.peek()
+	y.SMod(&x, y)
 	return nil, nil
 }
 
-func opExp(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	base, exponent := stack.pop(), stack.pop()
-	// some shortcuts
-	cmpToOne := exponent.Cmp(big1)
-	if cmpToOne < 0 { // Exponent is zero
-		// x ^ 0 == 1
-		stack.push(base.SetUint64(1))
-	} else if base.Sign() == 0 {
-		// 0 ^ y, if y != 0, == 0
-		stack.push(base.SetUint64(0))
-	} else if cmpToOne == 0 { // Exponent is one
-		// x ^ 1 == x
-		stack.push(base)
-	} else {
-		stack.push(math.Exp(base, exponent))
-		interpreter.intPool.put(base)
-	}
-	interpreter.intPool.put(exponent)
+func opExp(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	base, exponent := callContext.stack.pop(), callContext.stack.peek()
+	exponent.Exp(&base, exponent)
 	return nil, nil
 }
 
-func opSignExtend(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	back := stack.pop()
-	if back.Cmp(big.NewInt(31)) < 0 {
-		bit := uint(back.Uint64()*8 + 7)
-		num := stack.pop()
-		mask := back.Lsh(common.Big1, bit)
-		mask.Sub(mask, common.Big1)
-		if num.Bit(int(bit)) > 0 {
-			num.Or(num, mask.Not(mask))
-		} else {
-			num.And(num, mask)
-		}
-
-		stack.push(math.U256(num))
-	}
-
-	interpreter.intPool.put(back)
+func opSignExtend(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	back, num := callContext.stack.pop(), callContext.stack.peek()
+	num.ExtendSign(num, &back)
 	return nil, nil
 }
 
-func opNot(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	x := stack.peek()
-	math.U256(x.Not(x))
+func opNot(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	x := callContext.stack.peek()
+	x.Not(x)
 	return nil, nil
 }
 
-func opLt(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	x, y := stack.pop(), stack.peek()
-	if x.Cmp(y) < 0 {
-		y.SetUint64(1)
+func opLt(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	x, y := callContext.stack.pop(), callContext.stack.peek()
+	if x.Lt(y) {
+		y.SetOne()
 	} else {
-		y.SetUint64(0)
+		y.Clear()
 	}
-	interpreter.intPool.put(x)
 	return nil, nil
 }
 
-func opGt(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	x, y := stack.pop(), stack.peek()
-	if x.Cmp(y) > 0 {
-		y.SetUint64(1)
+func opGt(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	x, y := callContext.stack.pop(), callContext.stack.peek()
+	if x.Gt(y) {
+		y.SetOne()
 	} else {
-		y.SetUint64(0)
+		y.Clear()
 	}
-	interpreter.intPool.put(x)
 	return nil, nil
 }
 
-func opSlt(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	x, y := stack.pop(), stack.peek()
-
-	xSign := x.Cmp(tt255)
-	ySign := y.Cmp(tt255)
-
-	switch {
-	case xSign >= 0 && ySign < 0:
-		y.SetUint64(1)
-
-	case xSign < 0 && ySign >= 0:
-		y.SetUint64(0)
-
-	default:
-		if x.Cmp(y) < 0 {
-			y.SetUint64(1)
-		} else {
-			y.SetUint64(0)
-		}
+func opSlt(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	x, y := callContext.stack.pop(), callContext.stack.peek()
+	if x.Slt(y) {
+		y.SetOne()
+	} else {
+		y.Clear()
 	}
-	interpreter.intPool.put(x)
 	return nil, nil
 }
 
-func opSgt(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	x, y := stack.pop(), stack.peek()
-
-	xSign := x.Cmp(tt255)
-	ySign := y.Cmp(tt255)
-
-	switch {
-	case xSign >= 0 && ySign < 0:
-		y.SetUint64(0)
-
-	case xSign < 0 && ySign >= 0:
-		y.SetUint64(1)
-
-	default:
-		if x.Cmp(y) > 0 {
-			y.SetUint64(1)
-		} else {
-			y.SetUint64(0)
-		}
+func opSgt(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	x, y := callContext.stack.pop(), callContext.stack.peek()
+	if x.Sgt(y) {
+		y.SetOne()
+	} else {
+		y.Clear()
 	}
-	interpreter.intPool.put(x)
 	return nil, nil
 }
 
-func opEq(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	x, y := stack.pop(), stack.peek()
-	if x.Cmp(y) == 0 {
-		y.SetUint64(1)
+func opEq(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	x, y := callContext.stack.pop(), callContext.stack.peek()
+	if x.Eq(y) {
+		y.SetOne()
 	} else {
-		y.SetUint64(0)
+		y.Clear()
 	}
-	interpreter.intPool.put(x)
 	return nil, nil
 }
 
-func opIszero(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	x := stack.peek()
-	if x.Sign() > 0 {
-		x.SetUint64(0)
+func opIszero(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	x := callContext.stack.peek()
+	if x.IsZero() {
+		x.SetOne()
 	} else {
-		x.SetUint64(1)
+		x.Clear()
 	}
 	return nil, nil
 }
 
-func opAnd(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	x, y := stack.pop(), stack.pop()
-	stack.push(x.And(x, y))
-
-	interpreter.intPool.put(y)
+func opAnd(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	x, y := callContext.stack.pop(), callContext.stack.peek()
+	y.And(&x, y)
 	return nil, nil
 }
 
-func opOr(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	x, y := stack.pop(), stack.peek()
-	y.Or(x, y)
-
-	interpreter.intPool.put(x)
+func opOr(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	x, y := callContext.stack.pop(), callContext.stack.peek()
+	y.Or(&x, y)
 	return nil, nil
 }
 
-func opXor(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	x, y := stack.pop(), stack.peek()
-	y.Xor(x, y)
-
-	interpreter.intPool.put(x)
+func opXor(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	x, y := callContext.stack.pop(), callContext.stack.peek()
+	y.Xor(&x, y)
 	return nil, nil
 }
 
-func opByte(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	th, val := stack.pop(), stack.peek()
-	if th.Cmp(common.Big32) < 0 {
-		b := math.Byte(val, 32, int(th.Int64()))
-		val.SetUint64(uint64(b))
-	} else {
-		val.SetUint64(0)
-	}
-	interpreter.intPool.put(th)
+func opByte(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	th, val := callContext.stack.pop(), callContext.stack.peek()
+	val.Byte(&th)
 	return nil, nil
 }
 
-func opAddmod(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	x, y, z := stack.pop(), stack.pop(), stack.pop()
-	if z.Cmp(bigZero) > 0 {
-		x.Add(x, y)
-		x.Mod(x, z)
-		stack.push(math.U256(x))
+func opAddmod(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	x, y, z := callContext.stack.pop(), callContext.stack.pop(), callContext.stack.peek()
+	if z.IsZero() {
+		z.Clear()
 	} else {
-		stack.push(x.SetUint64(0))
+		z.AddMod(&x, &y, z)
 	}
-	interpreter.intPool.put(y, z)
 	return nil, nil
 }
 
-func opMulmod(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	x, y, z := stack.pop(), stack.pop(), stack.pop()
-	if z.Cmp(bigZero) > 0 {
-		x.Mul(x, y)
-		x.Mod(x, z)
-		stack.push(math.U256(x))
-	} else {
-		stack.push(x.SetUint64(0))
-	}
-	interpreter.intPool.put(y, z)
+func opMulmod(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	x, y, z := callContext.stack.pop(), callContext.stack.pop(), callContext.stack.peek()
+	z.MulMod(&x, &y, z)
 	return nil, nil
 }
 
 // opSHL implements Shift Left
 // The SHL instruction (shift left) pops 2 values from the stack, first arg1 and then arg2,
 // and pushes on the stack arg2 shifted to the left by arg1 number of bits.
-func opSHL(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+func opSHL(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
 	// Note, second operand is left in the stack; accumulate result into it, and no need to push it afterwards
-	shift, value := math.U256(stack.pop()), math.U256(stack.peek())
-	defer interpreter.intPool.put(shift) // First operand back into the pool
-
-	if shift.Cmp(common.Big256) >= 0 {
-		value.SetUint64(0)
-		return nil, nil
+	shift, value := callContext.stack.pop(), callContext.stack.peek()
+	if shift.LtUint64(256) {
+		value.Lsh(value, uint(shift.Uint64()))
+	} else {
+		value.Clear()
 	}
-	n := uint(shift.Uint64())
-	math.U256(value.Lsh(value, n))
-
 	return nil, nil
 }
 
 // opSHR implements Logical Shift Right
 // The SHR instruction (logical shift right) pops 2 values from the stack, first arg1 and then arg2,
 // and pushes on the stack arg2 shifted to the right by arg1 number of bits with zero fill.
-func opSHR(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+func opSHR(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
 	// Note, second operand is left in the stack; accumulate result into it, and no need to push it afterwards
-	shift, value := math.U256(stack.pop()), math.U256(stack.peek())
-	defer interpreter.intPool.put(shift) // First operand back into the pool
-
-	if shift.Cmp(common.Big256) >= 0 {
-		value.SetUint64(0)
-		return nil, nil
+	shift, value := callContext.stack.pop(), callContext.stack.peek()
+	if shift.LtUint64(256) {
+		value.Rsh(value, uint(shift.Uint64()))
+	} else {
+		value.Clear()
 	}
-	n := uint(shift.Uint64())
-	math.U256(value.Rsh(value, n))
-
 	return nil, nil
 }
 
 // opSAR implements Arithmetic Shift Right
 // The SAR instruction (arithmetic shift right) pops 2 values from the stack, first arg1 and then arg2,
 // and pushes on the stack arg2 shifted to the right by arg1 number of bits with sign extension.
-func opSAR(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	// Note, S256 returns (potentially) a new bigint, so we're popping, not peeking this one
-	shift, value := math.U256(stack.pop()), math.S256(stack.pop())
-	defer interpreter.intPool.put(shift) // First operand back into the pool
-
-	if shift.Cmp(common.Big256) >= 0 {
+func opSAR(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	shift, value := callContext.stack.pop(), callContext.stack.peek()
+	if shift.GtUint64(256) {
 		if value.Sign() >= 0 {
-			value.SetUint64(0)
+			value.Clear()
 		} else {
-			value.SetInt64(-1)
+			// Max negative shift: all bits set
+			value.SetAllOne()
 		}
-		stack.push(math.U256(value))
 		return nil, nil
 	}
 	n := uint(shift.Uint64())
-	value.Rsh(value, n)
-	stack.push(math.U256(value))
-
+	value.SRsh(value, n)
 	return nil, nil
 }
 
-func opSha3(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	offset, size := stack.pop(), stack.pop()
-	data := memory.Get(offset.Int64(), size.Int64())
+func opSha3(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	offset, size := callContext.stack.pop(), callContext.stack.peek()
+	data := callContext.memory.GetPtr(int64(offset.Uint64()), int64(size.Uint64()))
 
 	if interpreter.hasher == nil {
 		interpreter.hasher = sha3.NewLegacyKeccak256().(keccakState)
@@ -398,127 +248,154 @@ func opSha3(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory
 	if evm.vmConfig.EnablePreimageRecording {
 		evm.StateDB.AddPreimage(interpreter.hasherBuf, data)
 	}
-	stack.push(interpreter.intPool.get().SetBytes(interpreter.hasherBuf[:]))
 
-	interpreter.intPool.put(offset, size)
+	size.SetBytes(interpreter.hasherBuf[:])
 	return nil, nil
 }
-
-func opAddress(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	stack.push(interpreter.intPool.get().SetBytes(contract.Address().Bytes()))
+func opAddress(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	callContext.stack.push(new(uint256.Int).SetBytes(callContext.contract.Address().Bytes()))
 	return nil, nil
 }
 
-func opBalance(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	slot := stack.peek()
-	slot.Set(interpreter.evm.StateDB.GetBalance(common.BigToAddress(slot)))
+func opBalance(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	slot := callContext.stack.peek()
+	address := common.Address(slot.Bytes20())
+	slot.SetFromBig(interpreter.evm.StateDB.GetBalance(address))
 	return nil, nil
 }
 
-func opBalanceMultiCoin(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	addr, cid := stack.pop(), stack.pop()
-	stack.push(interpreter.evm.StateDB.GetBalanceMultiCoin(common.BigToAddress(addr), common.BigToHash(cid)))
+func opBalanceMultiCoin(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	addr, cid := callContext.stack.pop(), callContext.stack.pop()
+	res, err := uint256.FromBig(interpreter.evm.StateDB.GetBalanceMultiCoin(
+		common.BigToAddress(addr.ToBig()), common.BigToHash(cid.ToBig())))
+	if err {
+		return nil, errors.New("balance overflow")
+	}
+	callContext.stack.push(res)
 	return nil, nil
 }
 
-func opOrigin(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	stack.push(interpreter.intPool.get().SetBytes(interpreter.evm.Origin.Bytes()))
+func opOrigin(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	callContext.stack.push(new(uint256.Int).SetBytes(interpreter.evm.Origin.Bytes()))
 	return nil, nil
 }
-
-func opCaller(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	stack.push(interpreter.intPool.get().SetBytes(contract.Caller().Bytes()))
+func opCaller(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	callContext.stack.push(new(uint256.Int).SetBytes(callContext.contract.Caller().Bytes()))
 	return nil, nil
 }
 
-func opCallValue(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	stack.push(interpreter.intPool.get().Set(contract.value))
+func opCallValue(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	v, _ := uint256.FromBig(callContext.contract.value)
+	callContext.stack.push(v)
 	return nil, nil
 }
 
-func opCallDataLoad(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	stack.push(interpreter.intPool.get().SetBytes(getDataBig(contract.Input, stack.pop(), big32)))
+func opCallDataLoad(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	x := callContext.stack.peek()
+	if offset, overflow := x.Uint64WithOverflow(); !overflow {
+		data := getData(callContext.contract.Input, offset, 32)
+		x.SetBytes(data)
+	} else {
+		x.Clear()
+	}
 	return nil, nil
 }
 
-func opCallDataSize(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	stack.push(interpreter.intPool.get().SetInt64(int64(len(contract.Input))))
+func opCallDataSize(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	callContext.stack.push(new(uint256.Int).SetUint64(uint64(len(callContext.contract.Input))))
 	return nil, nil
 }
 
-func opCallDataCopy(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+func opCallDataCopy(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
 	var (
-		memOffset  = stack.pop()
-		dataOffset = stack.pop()
-		length     = stack.pop()
+		memOffset  = callContext.stack.pop()
+		dataOffset = callContext.stack.pop()
+		length     = callContext.stack.pop()
 	)
-	memory.Set(memOffset.Uint64(), length.Uint64(), getDataBig(contract.Input, dataOffset, length))
+	dataOffset64, overflow := dataOffset.Uint64WithOverflow()
+	if overflow {
+		dataOffset64 = 0xffffffffffffffff
+	}
+	// These values are checked for overflow during gas cost calculation
+	memOffset64 := memOffset.Uint64()
+	length64 := length.Uint64()
+	callContext.memory.Set(memOffset64, length64, getData(callContext.contract.Input, dataOffset64, length64))
 
-	interpreter.intPool.put(memOffset, dataOffset, length)
 	return nil, nil
 }
 
-func opReturnDataSize(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	stack.push(interpreter.intPool.get().SetUint64(uint64(len(interpreter.returnData))))
+func opReturnDataSize(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	callContext.stack.push(new(uint256.Int).SetUint64(uint64(len(interpreter.returnData))))
 	return nil, nil
 }
 
-func opReturnDataCopy(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+func opReturnDataCopy(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
 	var (
-		memOffset  = stack.pop()
-		dataOffset = stack.pop()
-		length     = stack.pop()
-
-		end = interpreter.intPool.get().Add(dataOffset, length)
+		memOffset  = callContext.stack.pop()
+		dataOffset = callContext.stack.pop()
+		length     = callContext.stack.pop()
 	)
-	defer interpreter.intPool.put(memOffset, dataOffset, length, end)
 
-	if !end.IsUint64() || uint64(len(interpreter.returnData)) < end.Uint64() {
-		return nil, errReturnDataOutOfBounds
+	offset64, overflow := dataOffset.Uint64WithOverflow()
+	if overflow {
+		return nil, ErrReturnDataOutOfBounds
 	}
-	memory.Set(memOffset.Uint64(), length.Uint64(), interpreter.returnData[dataOffset.Uint64():end.Uint64()])
-
+	// we can reuse dataOffset now (aliasing it for clarity)
+	var end = dataOffset
+	end.Add(&dataOffset, &length)
+	end64, overflow := end.Uint64WithOverflow()
+	if overflow || uint64(len(interpreter.returnData)) < end64 {
+		return nil, ErrReturnDataOutOfBounds
+	}
+	callContext.memory.Set(memOffset.Uint64(), length.Uint64(), interpreter.returnData[offset64:end64])
 	return nil, nil
 }
 
-func opExtCodeSize(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	slot := stack.peek()
-	slot.SetUint64(uint64(interpreter.evm.StateDB.GetCodeSize(common.BigToAddress(slot))))
-
+func opExtCodeSize(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	slot := callContext.stack.peek()
+	slot.SetUint64(uint64(interpreter.evm.StateDB.GetCodeSize(common.Address(slot.Bytes20()))))
 	return nil, nil
 }
 
-func opCodeSize(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	l := interpreter.intPool.get().SetInt64(int64(len(contract.Code)))
-	stack.push(l)
-
+func opCodeSize(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	l := new(uint256.Int)
+	l.SetUint64(uint64(len(callContext.contract.Code)))
+	callContext.stack.push(l)
 	return nil, nil
 }
 
-func opCodeCopy(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+func opCodeCopy(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
 	var (
-		memOffset  = stack.pop()
-		codeOffset = stack.pop()
-		length     = stack.pop()
+		memOffset  = callContext.stack.pop()
+		codeOffset = callContext.stack.pop()
+		length     = callContext.stack.pop()
 	)
-	codeCopy := getDataBig(contract.Code, codeOffset, length)
-	memory.Set(memOffset.Uint64(), length.Uint64(), codeCopy)
+	uint64CodeOffset, overflow := codeOffset.Uint64WithOverflow()
+	if overflow {
+		uint64CodeOffset = 0xffffffffffffffff
+	}
+	codeCopy := getData(callContext.contract.Code, uint64CodeOffset, length.Uint64())
+	callContext.memory.Set(memOffset.Uint64(), length.Uint64(), codeCopy)
 
-	interpreter.intPool.put(memOffset, codeOffset, length)
 	return nil, nil
 }
 
-func opExtCodeCopy(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+func opExtCodeCopy(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
 	var (
-		addr       = common.BigToAddress(stack.pop())
+		stack      = callContext.stack
+		a          = stack.pop()
 		memOffset  = stack.pop()
 		codeOffset = stack.pop()
 		length     = stack.pop()
 	)
-	codeCopy := getDataBig(interpreter.evm.StateDB.GetCode(addr), codeOffset, length)
-	memory.Set(memOffset.Uint64(), length.Uint64(), codeCopy)
+	uint64CodeOffset, overflow := codeOffset.Uint64WithOverflow()
+	if overflow {
+		uint64CodeOffset = 0xffffffffffffffff
+	}
+	addr := common.Address(a.Bytes20())
+	codeCopy := getData(interpreter.evm.StateDB.GetCode(addr), uint64CodeOffset, length.Uint64())
+	callContext.memory.Set(memOffset.Uint64(), length.Uint64(), codeCopy)
 
-	interpreter.intPool.put(memOffset, codeOffset, length)
 	return nil, nil
 }
 
@@ -548,398 +425,482 @@ func opExtCodeCopy(pc *uint64, interpreter *EVMInterpreter, contract *Contract,
 //
 //   (6) Caller tries to get the code hash for an account which is marked as deleted,
 // this account should be regarded as a non-existent account and zero should be returned.
-func opExtCodeHash(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	slot := stack.peek()
-	address := common.BigToAddress(slot)
+func opExtCodeHash(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	slot := callContext.stack.peek()
+	address := common.Address(slot.Bytes20())
 	if interpreter.evm.StateDB.Empty(address) {
-		slot.SetUint64(0)
+		slot.Clear()
 	} else {
 		slot.SetBytes(interpreter.evm.StateDB.GetCodeHash(address).Bytes())
 	}
 	return nil, nil
 }
 
-func opGasprice(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	stack.push(interpreter.intPool.get().Set(interpreter.evm.GasPrice))
+func opGasprice(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	v, _ := uint256.FromBig(interpreter.evm.GasPrice)
+	callContext.stack.push(v)
 	return nil, nil
 }
 
-func opBlockhash(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	num := stack.pop()
-
-	n := interpreter.intPool.get().Sub(interpreter.evm.BlockNumber, common.Big257)
-	if num.Cmp(n) > 0 && num.Cmp(interpreter.evm.BlockNumber) < 0 {
-		stack.push(interpreter.evm.GetHash(num.Uint64()).Big())
+func opBlockhash(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	num := callContext.stack.peek()
+	num64, overflow := num.Uint64WithOverflow()
+	if overflow {
+		num.Clear()
+		return nil, nil
+	}
+	var upper, lower uint64
+	upper = interpreter.evm.BlockNumber.Uint64()
+	if upper < 257 {
+		lower = 0
 	} else {
-		stack.push(interpreter.intPool.getZero())
+		lower = upper - 256
+	}
+	if num64 >= lower && num64 < upper {
+		num.SetBytes(interpreter.evm.GetHash(num64).Bytes())
+	} else {
+		num.Clear()
 	}
-	interpreter.intPool.put(num, n)
 	return nil, nil
 }
 
-func opCoinbase(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	stack.push(interpreter.intPool.get().SetBytes(interpreter.evm.Coinbase.Bytes()))
+func opCoinbase(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	callContext.stack.push(new(uint256.Int).SetBytes(interpreter.evm.Coinbase.Bytes()))
 	return nil, nil
 }
 
-func opTimestamp(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	stack.push(math.U256(interpreter.intPool.get().Set(interpreter.evm.Time)))
+func opTimestamp(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	v, _ := uint256.FromBig(interpreter.evm.Time)
+	callContext.stack.push(v)
 	return nil, nil
 }
 
-func opNumber(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	stack.push(math.U256(interpreter.intPool.get().Set(interpreter.evm.BlockNumber)))
+func opNumber(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	v, _ := uint256.FromBig(interpreter.evm.BlockNumber)
+	callContext.stack.push(v)
 	return nil, nil
 }
 
-func opDifficulty(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	stack.push(math.U256(interpreter.intPool.get().Set(interpreter.evm.Difficulty)))
+func opDifficulty(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	v, _ := uint256.FromBig(interpreter.evm.Difficulty)
+	callContext.stack.push(v)
 	return nil, nil
 }
 
-func opGasLimit(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	stack.push(math.U256(interpreter.intPool.get().SetUint64(interpreter.evm.GasLimit)))
+func opGasLimit(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	callContext.stack.push(new(uint256.Int).SetUint64(interpreter.evm.GasLimit))
 	return nil, nil
 }
 
-func opPop(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	interpreter.intPool.put(stack.pop())
+func opPop(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	callContext.stack.pop()
 	return nil, nil
 }
 
-func opMload(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	offset := stack.pop()
-	val := interpreter.intPool.get().SetBytes(memory.Get(offset.Int64(), 32))
-	stack.push(val)
-
-	interpreter.intPool.put(offset)
+func opMload(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	v := callContext.stack.peek()
+	offset := int64(v.Uint64())
+	v.SetBytes(callContext.memory.GetPtr(offset, 32))
 	return nil, nil
 }
 
-func opMstore(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+func opMstore(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
 	// pop value of the stack
-	mStart, val := stack.pop(), stack.pop()
-	memory.Set32(mStart.Uint64(), val)
-
-	interpreter.intPool.put(mStart, val)
+	mStart, val := callContext.stack.pop(), callContext.stack.pop()
+	callContext.memory.Set32(mStart.Uint64(), &val)
 	return nil, nil
 }
 
-func opMstore8(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	off, val := stack.pop().Int64(), stack.pop().Int64()
-	memory.store[off] = byte(val & 0xff)
-
+func opMstore8(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	off, val := callContext.stack.pop(), callContext.stack.pop()
+	callContext.memory.store[off.Uint64()] = byte(val.Uint64())
 	return nil, nil
 }
 
-func opSload(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	loc := stack.peek()
-	val := interpreter.evm.StateDB.GetState(contract.Address(), common.BigToHash(loc))
+func opSload(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	loc := callContext.stack.peek()
+	hash := common.Hash(loc.Bytes32())
+	val := interpreter.evm.StateDB.GetState(callContext.contract.Address(), hash)
 	loc.SetBytes(val.Bytes())
 	return nil, nil
 }
 
-func opSstore(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	loc := common.BigToHash(stack.pop())
-	val := stack.pop()
-	if err := interpreter.evm.StateDB.SetState(contract.Address(), loc, common.BigToHash(val)); err != nil {
+func opSstore(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	loc := callContext.stack.pop()
+	val := callContext.stack.pop()
+	if err := interpreter.evm.StateDB.SetState(callContext.contract.Address(),
+		common.Hash(loc.Bytes32()), common.Hash(val.Bytes32())); err != nil {
 		return nil, err
 	}
-	interpreter.intPool.put(val)
 	return nil, nil
 }
 
-func opJump(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	pos := stack.pop()
-	if !contract.validJumpdest(pos) {
-		return nil, errInvalidJump
+func opJump(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	pos := callContext.stack.pop()
+	if !callContext.contract.validJumpdest(&pos) {
+		return nil, ErrInvalidJump
 	}
 	*pc = pos.Uint64()
-
-	interpreter.intPool.put(pos)
 	return nil, nil
 }
 
-func opJumpi(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	pos, cond := stack.pop(), stack.pop()
-	if cond.Sign() != 0 {
-		if !contract.validJumpdest(pos) {
-			return nil, errInvalidJump
+func opJumpi(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	pos, cond := callContext.stack.pop(), callContext.stack.pop()
+	if !cond.IsZero() {
+		if !callContext.contract.validJumpdest(&pos) {
+			return nil, ErrInvalidJump
 		}
 		*pc = pos.Uint64()
 	} else {
 		*pc++
 	}
+	return nil, nil
+}
+
+func opJumpdest(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	return nil, nil
+}
 
-	interpreter.intPool.put(pos, cond)
+func opBeginSub(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	return nil, ErrInvalidSubroutineEntry
+}
+
+func opJumpSub(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	if len(callContext.rstack.data) >= 1023 {
+		return nil, ErrReturnStackExceeded
+	}
+	pos := callContext.stack.pop()
+	if !pos.IsUint64() {
+		return nil, ErrInvalidJump
+	}
+	posU64 := pos.Uint64()
+	if !callContext.contract.validJumpSubdest(posU64) {
+		return nil, ErrInvalidJump
+	}
+	callContext.rstack.push(uint32(*pc))
+	*pc = posU64 + 1
 	return nil, nil
 }
 
-func opJumpdest(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+func opReturnSub(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	if len(callContext.rstack.data) == 0 {
+		return nil, ErrInvalidRetsub
+	}
+	// Other than the check that the return stack is not empty, there is no
+	// need to validate the pc from 'returns', since we only ever push valid
+	//values onto it via jumpsub.
+	*pc = uint64(callContext.rstack.pop()) + 1
 	return nil, nil
 }
 
-func opPc(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	stack.push(interpreter.intPool.get().SetUint64(*pc))
+func opPc(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	callContext.stack.push(new(uint256.Int).SetUint64(*pc))
 	return nil, nil
 }
 
-func opMsize(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	stack.push(interpreter.intPool.get().SetInt64(int64(memory.Len())))
+func opMsize(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	callContext.stack.push(new(uint256.Int).SetUint64(uint64(callContext.memory.Len())))
 	return nil, nil
 }
 
-func opGas(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	stack.push(interpreter.intPool.get().SetUint64(contract.Gas))
+func opGas(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	callContext.stack.push(new(uint256.Int).SetUint64(callContext.contract.Gas))
 	return nil, nil
 }
 
-func opCreate(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+func opCreate(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
 	var (
-		value        = stack.pop()
-		offset, size = stack.pop(), stack.pop()
-		input        = memory.Get(offset.Int64(), size.Int64())
-		gas          = contract.Gas
+		value        = callContext.stack.pop()
+		offset, size = callContext.stack.pop(), callContext.stack.pop()
+		input        = callContext.memory.GetCopy(int64(offset.Uint64()), int64(size.Uint64()))
+		gas          = callContext.contract.Gas
 	)
 	if interpreter.evm.chainRules.IsEIP150 {
 		gas -= gas / 64
 	}
+	// reuse size int for stackvalue
+	stackvalue := size
 
-	contract.UseGas(gas)
-	res, addr, returnGas, suberr := interpreter.evm.Create(contract, input, gas, value)
+	callContext.contract.UseGas(gas)
+	//TODO: use uint256.Int instead of converting with toBig()
+	var bigVal = big0
+	if !value.IsZero() {
+		bigVal = value.ToBig()
+	}
+
+	res, addr, returnGas, suberr := interpreter.evm.Create(callContext.contract, input, gas, bigVal)
 	// Push item on the stack based on the returned error. If the ruleset is
 	// homestead we must check for CodeStoreOutOfGasError (homestead only
 	// rule) and treat as an error, if the ruleset is frontier we must
 	// ignore this error and pretend the operation was successful.
 	if interpreter.evm.chainRules.IsHomestead && suberr == ErrCodeStoreOutOfGas {
-		stack.push(interpreter.intPool.getZero())
+		stackvalue.Clear()
 	} else if suberr != nil && suberr != ErrCodeStoreOutOfGas {
-		stack.push(interpreter.intPool.getZero())
+		stackvalue.Clear()
 	} else {
-		stack.push(interpreter.intPool.get().SetBytes(addr.Bytes()))
+		stackvalue.SetBytes(addr.Bytes())
 	}
-	contract.Gas += returnGas
-	interpreter.intPool.put(value, offset, size)
+	callContext.stack.push(&stackvalue)
+	callContext.contract.Gas += returnGas
 
-	if suberr == errExecutionReverted {
+	if suberr == ErrExecutionReverted {
 		return res, nil
 	}
 	return nil, nil
 }
 
-func opCreate2(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+func opCreate2(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
 	var (
-		endowment    = stack.pop()
-		offset, size = stack.pop(), stack.pop()
-		salt         = stack.pop()
-		input        = memory.Get(offset.Int64(), size.Int64())
-		gas          = contract.Gas
+		endowment    = callContext.stack.pop()
+		offset, size = callContext.stack.pop(), callContext.stack.pop()
+		salt         = callContext.stack.pop()
+		input        = callContext.memory.GetCopy(int64(offset.Uint64()), int64(size.Uint64()))
+		gas          = callContext.contract.Gas
 	)
 
 	// Apply EIP150
 	gas -= gas / 64
-	contract.UseGas(gas)
-	res, addr, returnGas, suberr := interpreter.evm.Create2(contract, input, gas, endowment, salt)
+	callContext.contract.UseGas(gas)
+	// reuse size int for stackvalue
+	stackvalue := size
+	//TODO: use uint256.Int instead of converting with toBig()
+	bigEndowment := big0
+	if !endowment.IsZero() {
+		bigEndowment = endowment.ToBig()
+	}
+	res, addr, returnGas, suberr := interpreter.evm.Create2(callContext.contract, input, gas,
+		bigEndowment, &salt)
 	// Push item on the stack based on the returned error.
 	if suberr != nil {
-		stack.push(interpreter.intPool.getZero())
+		stackvalue.Clear()
 	} else {
-		stack.push(interpreter.intPool.get().SetBytes(addr.Bytes()))
+		stackvalue.SetBytes(addr.Bytes())
 	}
-	contract.Gas += returnGas
-	interpreter.intPool.put(endowment, offset, size, salt)
+	callContext.stack.push(&stackvalue)
+	callContext.contract.Gas += returnGas
 
-	if suberr == errExecutionReverted {
+	if suberr == ErrExecutionReverted {
 		return res, nil
 	}
 	return nil, nil
 }
 
-func opCall(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+func opCall(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	stack := callContext.stack
 	// Pop gas. The actual gas in interpreter.evm.callGasTemp.
-	interpreter.intPool.put(stack.pop())
+	// We can use this as a temporary value
+	temp := stack.pop()
 	gas := interpreter.evm.callGasTemp
 	// Pop other call parameters.
 	addr, value, inOffset, inSize, retOffset, retSize := stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop()
-	toAddr := common.BigToAddress(addr)
-	value = math.U256(value)
+	toAddr := common.Address(addr.Bytes20())
 	// Get the arguments from the memory.
-	args := memory.Get(inOffset.Int64(), inSize.Int64())
+	args := callContext.memory.GetPtr(int64(inOffset.Uint64()), int64(inSize.Uint64()))
 
-	if value.Sign() != 0 {
+	var bigVal = big0
+	//TODO: use uint256.Int instead of converting with toBig()
+	// By using big0 here, we save an alloc for the most common case (non-ether-transferring contract calls),
+	// but it would make more sense to extend the usage of uint256.Int
+	if !value.IsZero() {
 		gas += params.CallStipend
+		bigVal = value.ToBig()
 	}
-	ret, returnGas, err := interpreter.evm.Call(contract, toAddr, args, gas, value)
+
+	ret, returnGas, err := interpreter.evm.Call(callContext.contract, toAddr, args, gas, bigVal)
+
 	if err != nil {
-		stack.push(interpreter.intPool.getZero())
+		temp.Clear()
 	} else {
-		stack.push(interpreter.intPool.get().SetUint64(1))
+		temp.SetOne()
 	}
-	if err == nil || err == errExecutionReverted {
-		memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
+	stack.push(&temp)
+	if err == nil || err == ErrExecutionReverted {
+		callContext.memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
 	}
-	contract.Gas += returnGas
+	callContext.contract.Gas += returnGas
 
-	interpreter.intPool.put(addr, value, inOffset, inSize, retOffset, retSize)
 	return ret, nil
 }
 
-func opCallExpert(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+func opCallExpert(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	stack := callContext.stack
 	// Pop gas. The actual gas in interpreter.evm.callGasTemp.
-	interpreter.intPool.put(stack.pop())
+	// We can use this as a temporary value
+	temp := stack.pop()
 	gas := interpreter.evm.callGasTemp
 	// Pop other call parameters.
 	addr, value, cid, value2, inOffset, inSize, retOffset, retSize := stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop()
-	toAddr := common.BigToAddress(addr)
-	coinID := common.BigToHash(cid)
-	value = math.U256(value)
-	value2 = math.U256(value2)
+	toAddr := common.Address(addr.Bytes20())
+	coinID := common.BigToHash(cid.ToBig())
 	// Get the arguments from the memory.
-	args := memory.Get(inOffset.Int64(), inSize.Int64())
+	args := callContext.memory.GetPtr(int64(inOffset.Uint64()), int64(inSize.Uint64()))
 
-	if value.Sign() != 0 {
+	var bigVal = big0
+	//TODO: use uint256.Int instead of converting with toBig()
+	// By using big0 here, we save an alloc for the most common case (non-ether-transferring contract calls),
+	// but it would make more sense to extend the usage of uint256.Int
+	if !value.IsZero() {
 		gas += params.CallStipend
+		bigVal = value.ToBig()
 	}
-	ret, returnGas, err := interpreter.evm.CallExpert(contract, toAddr, args, gas, value, &coinID, value2)
+
+	var bigVal2 = big0
+	//TODO: use uint256.Int instead of converting with toBig()
+	// By using big0 here, we save an alloc for the most common case (non-ether-transferring contract calls),
+	// but it would make more sense to extend the usage of uint256.Int
+	if !value2.IsZero() {
+		bigVal2 = value2.ToBig()
+	}
+
+	ret, returnGas, err := interpreter.evm.CallExpert(callContext.contract, toAddr, args, gas, bigVal, &coinID, bigVal2)
+
 	if err != nil {
-		stack.push(interpreter.intPool.getZero())
+		temp.Clear()
 	} else {
-		stack.push(interpreter.intPool.get().SetUint64(1))
+		temp.SetOne()
 	}
-	if err == nil || err == errExecutionReverted {
-		memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
+	stack.push(&temp)
+	if err == nil || err == ErrExecutionReverted {
+		callContext.memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
 	}
-	contract.Gas += returnGas
+	callContext.contract.Gas += returnGas
 
-	interpreter.intPool.put(addr, value, inOffset, inSize, retOffset, retSize)
 	return ret, nil
 }
-
-func opCallCode(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+func opCallCode(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
 	// Pop gas. The actual gas is in interpreter.evm.callGasTemp.
-	interpreter.intPool.put(stack.pop())
+	stack := callContext.stack
+	// We use it as a temporary value
+	temp := stack.pop()
 	gas := interpreter.evm.callGasTemp
 	// Pop other call parameters.
 	addr, value, inOffset, inSize, retOffset, retSize := stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop()
-	toAddr := common.BigToAddress(addr)
-	value = math.U256(value)
+	toAddr := common.Address(addr.Bytes20())
 	// Get arguments from the memory.
-	args := memory.Get(inOffset.Int64(), inSize.Int64())
+	args := callContext.memory.GetPtr(int64(inOffset.Uint64()), int64(inSize.Uint64()))
 
-	if value.Sign() != 0 {
+	//TODO: use uint256.Int instead of converting with toBig()
+	var bigVal = big0
+	if !value.IsZero() {
 		gas += params.CallStipend
+		bigVal = value.ToBig()
 	}
-	ret, returnGas, err := interpreter.evm.CallCode(contract, toAddr, args, gas, value)
+
+	ret, returnGas, err := interpreter.evm.CallCode(callContext.contract, toAddr, args, gas, bigVal)
 	if err != nil {
-		stack.push(interpreter.intPool.getZero())
+		temp.Clear()
 	} else {
-		stack.push(interpreter.intPool.get().SetUint64(1))
+		temp.SetOne()
 	}
-	if err == nil || err == errExecutionReverted {
-		memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
+	stack.push(&temp)
+	if err == nil || err == ErrExecutionReverted {
+		callContext.memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
 	}
-	contract.Gas += returnGas
+	callContext.contract.Gas += returnGas
 
-	interpreter.intPool.put(addr, value, inOffset, inSize, retOffset, retSize)
 	return ret, nil
 }
 
-func opDelegateCall(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+func opDelegateCall(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	stack := callContext.stack
 	// Pop gas. The actual gas is in interpreter.evm.callGasTemp.
-	interpreter.intPool.put(stack.pop())
+	// We use it as a temporary value
+	temp := stack.pop()
 	gas := interpreter.evm.callGasTemp
 	// Pop other call parameters.
 	addr, inOffset, inSize, retOffset, retSize := stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop()
-	toAddr := common.BigToAddress(addr)
+	toAddr := common.Address(addr.Bytes20())
 	// Get arguments from the memory.
-	args := memory.Get(inOffset.Int64(), inSize.Int64())
+	args := callContext.memory.GetPtr(int64(inOffset.Uint64()), int64(inSize.Uint64()))
 
-	ret, returnGas, err := interpreter.evm.DelegateCall(contract, toAddr, args, gas)
+	ret, returnGas, err := interpreter.evm.DelegateCall(callContext.contract, toAddr, args, gas)
 	if err != nil {
-		stack.push(interpreter.intPool.getZero())
+		temp.Clear()
 	} else {
-		stack.push(interpreter.intPool.get().SetUint64(1))
+		temp.SetOne()
 	}
-	if err == nil || err == errExecutionReverted {
-		memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
+	stack.push(&temp)
+	if err == nil || err == ErrExecutionReverted {
+		callContext.memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
 	}
-	contract.Gas += returnGas
+	callContext.contract.Gas += returnGas
 
-	interpreter.intPool.put(addr, inOffset, inSize, retOffset, retSize)
 	return ret, nil
 }
 
-func opStaticCall(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+func opStaticCall(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
 	// Pop gas. The actual gas is in interpreter.evm.callGasTemp.
-	interpreter.intPool.put(stack.pop())
+	stack := callContext.stack
+	// We use it as a temporary value
+	temp := stack.pop()
 	gas := interpreter.evm.callGasTemp
 	// Pop other call parameters.
 	addr, inOffset, inSize, retOffset, retSize := stack.pop(), stack.pop(), stack.pop(), stack.pop(), stack.pop()
-	toAddr := common.BigToAddress(addr)
+	toAddr := common.Address(addr.Bytes20())
 	// Get arguments from the memory.
-	args := memory.Get(inOffset.Int64(), inSize.Int64())
+	args := callContext.memory.GetPtr(int64(inOffset.Uint64()), int64(inSize.Uint64()))
 
-	ret, returnGas, err := interpreter.evm.StaticCall(contract, toAddr, args, gas)
+	ret, returnGas, err := interpreter.evm.StaticCall(callContext.contract, toAddr, args, gas)
 	if err != nil {
-		stack.push(interpreter.intPool.getZero())
+		temp.Clear()
 	} else {
-		stack.push(interpreter.intPool.get().SetUint64(1))
+		temp.SetOne()
 	}
-	if err == nil || err == errExecutionReverted {
-		memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
+	stack.push(&temp)
+	if err == nil || err == ErrExecutionReverted {
+		callContext.memory.Set(retOffset.Uint64(), retSize.Uint64(), ret)
 	}
-	contract.Gas += returnGas
+	callContext.contract.Gas += returnGas
 
-	interpreter.intPool.put(addr, inOffset, inSize, retOffset, retSize)
 	return ret, nil
 }
 
-func opReturn(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	offset, size := stack.pop(), stack.pop()
-	ret := memory.GetPtr(offset.Int64(), size.Int64())
+func opReturn(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	offset, size := callContext.stack.pop(), callContext.stack.pop()
+	ret := callContext.memory.GetPtr(int64(offset.Uint64()), int64(size.Uint64()))
 
-	interpreter.intPool.put(offset, size)
 	return ret, nil
 }
 
-func opRevert(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	offset, size := stack.pop(), stack.pop()
-	ret := memory.GetPtr(offset.Int64(), size.Int64())
+func opRevert(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	offset, size := callContext.stack.pop(), callContext.stack.pop()
+	ret := callContext.memory.GetPtr(int64(offset.Uint64()), int64(size.Uint64()))
 
-	interpreter.intPool.put(offset, size)
 	return ret, nil
 }
 
-func opStop(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+func opStop(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
 	return nil, nil
 }
 
-func opSuicide(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	balance := interpreter.evm.StateDB.GetBalance(contract.Address())
-	interpreter.evm.StateDB.AddBalance(common.BigToAddress(stack.pop()), balance)
-
-	interpreter.evm.StateDB.Suicide(contract.Address())
+func opSuicide(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	beneficiary := callContext.stack.pop()
+	balance := interpreter.evm.StateDB.GetBalance(callContext.contract.Address())
+	interpreter.evm.StateDB.AddBalance(common.Address(beneficiary.Bytes20()), balance)
+	interpreter.evm.StateDB.Suicide(callContext.contract.Address())
 	return nil, nil
 }
 
-func opEMC(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-	return nil, interpreter.evm.StateDB.EnableMultiCoin(contract.Address())
+func opEMC(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	return nil, interpreter.evm.StateDB.EnableMultiCoin(callContext.contract.Address())
 }
 
 // following functions are used by the instruction jump  table
 
 // make log instruction function
 func makeLog(size int) executionFunc {
-	return func(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+	return func(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
 		topics := make([]common.Hash, size)
+		stack := callContext.stack
 		mStart, mSize := stack.pop(), stack.pop()
 		for i := 0; i < size; i++ {
-			topics[i] = common.BigToHash(stack.pop())
+			addr := stack.pop()
+			topics[i] = common.Hash(addr.Bytes32())
 		}
 
-		d := memory.Get(mStart.Int64(), mSize.Int64())
+		d := callContext.memory.GetCopy(int64(mStart.Uint64()), int64(mSize.Uint64()))
 		interpreter.evm.StateDB.AddLog(&types.Log{
-			Address: contract.Address(),
+			Address: callContext.contract.Address(),
 			Topics:  topics,
 			Data:    d,
 			// This is a non-consensus field, but assigned here because
@@ -947,30 +908,29 @@ func makeLog(size int) executionFunc {
 			BlockNumber: interpreter.evm.BlockNumber.Uint64(),
 		})
 
-		interpreter.intPool.put(mStart, mSize)
 		return nil, nil
 	}
 }
 
 // opPush1 is a specialized version of pushN
-func opPush1(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
+func opPush1(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
 	var (
-		codeLen = uint64(len(contract.Code))
-		integer = interpreter.intPool.get()
+		codeLen = uint64(len(callContext.contract.Code))
+		integer = new(uint256.Int)
 	)
 	*pc += 1
 	if *pc < codeLen {
-		stack.push(integer.SetUint64(uint64(contract.Code[*pc])))
+		callContext.stack.push(integer.SetUint64(uint64(callContext.contract.Code[*pc])))
 	} else {
-		stack.push(integer.SetUint64(0))
+		callContext.stack.push(integer.Clear())
 	}
 	return nil, nil
 }
 
 // make push instruction function
 func makePush(size uint64, pushByteSize int) executionFunc {
-	return func(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-		codeLen := len(contract.Code)
+	return func(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+		codeLen := len(callContext.contract.Code)
 
 		startMin := codeLen
 		if int(*pc+1) < startMin {
@@ -982,8 +942,9 @@ func makePush(size uint64, pushByteSize int) executionFunc {
 			endMin = startMin + pushByteSize
 		}
 
-		integer := interpreter.intPool.get()
-		stack.push(integer.SetBytes(common.RightPadBytes(contract.Code[startMin:endMin], pushByteSize)))
+		integer := new(uint256.Int)
+		callContext.stack.push(integer.SetBytes(common.RightPadBytes(
+			callContext.contract.Code[startMin:endMin], pushByteSize)))
 
 		*pc += size
 		return nil, nil
@@ -992,8 +953,8 @@ func makePush(size uint64, pushByteSize int) executionFunc {
 
 // make dup instruction function
 func makeDup(size int64) executionFunc {
-	return func(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-		stack.dup(interpreter.intPool, int(size))
+	return func(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+		callContext.stack.dup(int(size))
 		return nil, nil
 	}
 }
@@ -1002,8 +963,8 @@ func makeDup(size int64) executionFunc {
 func makeSwap(size int64) executionFunc {
 	// switch n + 1 otherwise n would be swapped with n
 	size++
-	return func(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error) {
-		stack.swap(int(size))
+	return func(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+		callContext.stack.swap(int(size))
 		return nil, nil
 	}
 }
diff --git a/core/vm/int_pool_verifier.go b/core/vm/int_pool_verifier.go
deleted file mode 100644
index 82fbfed..0000000
--- a/core/vm/int_pool_verifier.go
+++ /dev/null
@@ -1,31 +0,0 @@
-// Copyright 2017 The go-ethereum Authors
-// This file is part of the go-ethereum library.
-//
-// The go-ethereum library is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Lesser General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// The go-ethereum library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public License
-// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
-
-// +build VERIFY_EVM_INTEGER_POOL
-
-package vm
-
-import "fmt"
-
-const verifyPool = true
-
-func verifyIntegerPool(ip *intPool) {
-	for i, item := range ip.pool.data {
-		if item.Cmp(checkVal) != 0 {
-			panic(fmt.Sprintf("%d'th item failed aggressive pool check. Value was modified", i))
-		}
-	}
-}
diff --git a/core/vm/int_pool_verifier_empty.go b/core/vm/int_pool_verifier_empty.go
deleted file mode 100644
index a5f1dc0..0000000
--- a/core/vm/int_pool_verifier_empty.go
+++ /dev/null
@@ -1,23 +0,0 @@
-// Copyright 2017 The go-ethereum Authors
-// This file is part of the go-ethereum library.
-//
-// The go-ethereum library is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Lesser General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// The go-ethereum library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public License
-// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
-
-// +build !VERIFY_EVM_INTEGER_POOL
-
-package vm
-
-const verifyPool = false
-
-func verifyIntegerPool(ip *intPool) {}
diff --git a/core/vm/interface.go b/core/vm/interface.go
index 7e2d324..4f95423 100644
--- a/core/vm/interface.go
+++ b/core/vm/interface.go
@@ -20,7 +20,7 @@ import (
 	"math/big"
 
 	"github.com/ava-labs/coreth/core/types"
-	"github.com/ava-labs/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common"
 )
 
 // StateDB is an EVM database for full state querying.
diff --git a/core/vm/interpreter.go b/core/vm/interpreter.go
index e23896a..a114a8d 100644
--- a/core/vm/interpreter.go
+++ b/core/vm/interpreter.go
@@ -17,13 +17,12 @@
 package vm
 
 import (
-	"fmt"
 	"hash"
 	"sync/atomic"
 
-	"github.com/ava-labs/go-ethereum/common"
-	"github.com/ava-labs/go-ethereum/common/math"
-	"github.com/ava-labs/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/math"
+	"github.com/ethereum/go-ethereum/log"
 )
 
 var (
@@ -40,7 +39,7 @@ type Config struct {
 	NoRecursion             bool   // Disables call, callcode, delegate call and create
 	EnablePreimageRecording bool   // Enables recording of SHA3/keccak preimages
 
-	JumpTable [256]operation // EVM instruction table, automatically populated if unset
+	JumpTable [256]*operation // EVM instruction table, automatically populated if unset
 
 	EWASMInterpreter string // External EWASM interpreter options
 	EVMInterpreter   string // External EVM interpreter options
@@ -70,6 +69,15 @@ type Interpreter interface {
 	CanRun([]byte) bool
 }
 
+// callCtx contains the things that are per-call, such as stack and memory,
+// but not transients like pc and gas
+type callCtx struct {
+	memory   *Memory
+	stack    *Stack
+	rstack   *ReturnStack
+	contract *Contract
+}
+
 // keccakState wraps sha3.state. In addition to the usual hash methods, it also supports
 // Read to get a variable amount of data from the hash state. Read is faster than Sum
 // because it doesn't copy the internal state, but also modifies the internal state.
@@ -83,8 +91,6 @@ type EVMInterpreter struct {
 	evm *EVM
 	cfg Config
 
-	intPool *intPool
-
 	hasher    keccakState // Keccak256 hasher instance shared across opcodes
 	hasherBuf common.Hash // Keccak256 hasher result array shared aross opcodes
 
@@ -97,9 +103,11 @@ func NewEVMInterpreter(evm *EVM, cfg Config) *EVMInterpreter {
 	// We use the STOP instruction whether to see
 	// the jump table was initialised. If it was not
 	// we'll set the default jump table.
-	if !cfg.JumpTable[STOP].valid {
+	if cfg.JumpTable[STOP] == nil {
 		var jt JumpTable
 		switch {
+		case evm.chainRules.IsYoloV1:
+			jt = yoloV1InstructionSet
 		case evm.chainRules.IsIstanbul:
 			jt = istanbulInstructionSet
 		case evm.chainRules.IsConstantinople:
@@ -136,7 +144,7 @@ func NewEVMInterpreter(evm *EVM, cfg Config) *EVMInterpreter {
 //
 // It's important to note that any errors returned by the interpreter should be
 // considered a revert-and-consume-all-gas operation except for
-// errExecutionReverted which means revert-and-keep-gas-left.
+// ErrExecutionReverted which means revert-and-keep-gas-left.
 func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (ret []byte, err error) {
 	if contract.Address() == BuiltinAddr {
 		self := AccountRef(contract.Caller())
@@ -145,13 +153,6 @@ func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (
 		}
 		contract.self = self
 	}
-	if in.intPool == nil {
-		in.intPool = poolOfIntPools.get()
-		defer func() {
-			poolOfIntPools.put(in.intPool)
-			in.intPool = nil
-		}()
-	}
 
 	// Increment the call depth which is restricted to 1024
 	in.evm.depth++
@@ -174,9 +175,16 @@ func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (
 	}
 
 	var (
-		op    OpCode        // current opcode
-		mem   = NewMemory() // bound memory
-		stack = newstack()  // local stack
+		op          OpCode             // current opcode
+		mem         = NewMemory()      // bound memory
+		stack       = newstack()       // local stack
+		returns     = newReturnStack() // local returns stack
+		callContext = &callCtx{
+			memory:   mem,
+			stack:    stack,
+			rstack:   returns,
+			contract: contract,
+		}
 		// For optimisation reason we're using uint64 as the program counter.
 		// It's theoretically possible to go above 2^64. The YP defines the PC
 		// to be uint256. Practically much less so feasible.
@@ -188,18 +196,22 @@ func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (
 		logged  bool   // deferred Tracer should ignore already logged steps
 		res     []byte // result of the opcode execution function
 	)
+	// Don't move this deferrred function, it's placed before the capturestate-deferred method,
+	// so that it get's executed _after_: the capturestate needs the stacks before
+	// they are returned to the pools
+	defer func() {
+		returnStack(stack)
+		returnRStack(returns)
+	}()
 	contract.Input = input
 
-	// Reclaim the stack as an int pool when the execution stops
-	defer func() { in.intPool.put(stack.data...) }()
-
 	if in.cfg.Debug {
 		defer func() {
 			if err != nil {
 				if !logged {
-					in.cfg.Tracer.CaptureState(in.evm, pcCopy, op, gasCopy, cost, mem, stack, contract, in.evm.depth, err)
+					in.cfg.Tracer.CaptureState(in.evm, pcCopy, op, gasCopy, cost, mem, stack, returns, in.returnData, contract, in.evm.depth, err)
 				} else {
-					in.cfg.Tracer.CaptureFault(in.evm, pcCopy, op, gasCopy, cost, mem, stack, contract, in.evm.depth, err)
+					in.cfg.Tracer.CaptureFault(in.evm, pcCopy, op, gasCopy, cost, mem, stack, returns, contract, in.evm.depth, err)
 				}
 			}
 		}()
@@ -208,7 +220,12 @@ func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (
 	// explicit STOP, RETURN or SELFDESTRUCT is executed, an error occurred during
 	// the execution of one of the operations or until the done flag is set by the
 	// parent context.
-	for atomic.LoadInt32(&in.evm.abort) == 0 {
+	steps := 0
+	for {
+		steps++
+		if steps%1000 == 0 && atomic.LoadInt32(&in.evm.abort) != 0 {
+			break
+		}
 		if in.cfg.Debug {
 			// Capture pre-execution values for tracing.
 			logged, pcCopy, gasCopy = false, pc, contract.Gas
@@ -218,14 +235,14 @@ func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (
 		// enough stack items available to perform the operation.
 		op = contract.GetOp(pc)
 		operation := in.cfg.JumpTable[op]
-		if !operation.valid {
-			return nil, fmt.Errorf("invalid opcode 0x%x", int(op))
+		if operation == nil {
+			return nil, &ErrInvalidOpCode{opcode: op}
 		}
 		// Validate stack
 		if sLen := stack.len(); sLen < operation.minStack {
-			return nil, fmt.Errorf("stack underflow (%d <=> %d)", sLen, operation.minStack)
+			return nil, &ErrStackUnderflow{stackLen: sLen, required: operation.minStack}
 		} else if sLen > operation.maxStack {
-			return nil, fmt.Errorf("stack limit reached %d (%d)", sLen, operation.maxStack)
+			return nil, &ErrStackOverflow{stackLen: sLen, limit: operation.maxStack}
 		}
 		// If the operation is valid, enforce and write restrictions
 		if in.readOnly && in.evm.chainRules.IsByzantium {
@@ -235,7 +252,7 @@ func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (
 			// account to the others means the state is modified and should also
 			// return with an error.
 			if operation.writes || ((op == CALL || op == CALLEX) && stack.Back(2).Sign() != 0) {
-				return nil, errWriteProtection
+				return nil, ErrWriteProtection
 			}
 		}
 		// Static portion of gas
@@ -252,12 +269,12 @@ func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (
 		if operation.memorySize != nil {
 			memSize, overflow := operation.memorySize(stack)
 			if overflow {
-				return nil, errGasUintOverflow
+				return nil, ErrGasUintOverflow
 			}
 			// memory is expanded in words of 32 bytes. Gas
 			// is also calculated in words.
 			if memorySize, overflow = math.SafeMul(toWordSize(memSize), 32); overflow {
-				return nil, errGasUintOverflow
+				return nil, ErrGasUintOverflow
 			}
 		}
 		// Dynamic portion of gas
@@ -276,28 +293,23 @@ func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (
 		}
 
 		if in.cfg.Debug {
-			in.cfg.Tracer.CaptureState(in.evm, pc, op, gasCopy, cost, mem, stack, contract, in.evm.depth, err)
+			in.cfg.Tracer.CaptureState(in.evm, pc, op, gasCopy, cost, mem, stack, returns, in.returnData, contract, in.evm.depth, err)
 			logged = true
 		}
 
 		// execute the operation
-		res, err = operation.execute(&pc, in, contract, mem, stack)
-		// verifyPool is a build flag. Pool verification makes sure the integrity
-		// of the integer pool by comparing values to a default value.
-		if verifyPool {
-			verifyIntegerPool(in.intPool)
-		}
+		res, err = operation.execute(&pc, in, callContext)
 		// if the operation clears the return data (e.g. it has returning data)
 		// set the last return to the result of the operation.
 		if operation.returns {
-			in.returnData = res
+			in.returnData = common.CopyBytes(res)
 		}
 
 		switch {
 		case err != nil:
 			return nil, err
 		case operation.reverts:
-			return res, errExecutionReverted
+			return res, ErrExecutionReverted
 		case operation.halts:
 			return res, nil
 		case !operation.jumps:
diff --git a/core/vm/intpool.go b/core/vm/intpool.go
deleted file mode 100644
index 917a78d..0000000
--- a/core/vm/intpool.go
+++ /dev/null
@@ -1,106 +0,0 @@
-// Copyright 2017 The go-ethereum Authors
-// This file is part of the go-ethereum library.
-//
-// The go-ethereum library is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Lesser General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// The go-ethereum library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public License
-// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
-
-package vm
-
-import (
-	"math/big"
-	"sync"
-)
-
-var checkVal = big.NewInt(-42)
-
-const poolLimit = 256
-
-// intPool is a pool of big integers that
-// can be reused for all big.Int operations.
-type intPool struct {
-	pool *Stack
-}
-
-func newIntPool() *intPool {
-	return &intPool{pool: newstack()}
-}
-
-// get retrieves a big int from the pool, allocating one if the pool is empty.
-// Note, the returned int's value is arbitrary and will not be zeroed!
-func (p *intPool) get() *big.Int {
-	if p.pool.len() > 0 {
-		return p.pool.pop()
-	}
-	return new(big.Int)
-}
-
-// getZero retrieves a big int from the pool, setting it to zero or allocating
-// a new one if the pool is empty.
-func (p *intPool) getZero() *big.Int {
-	if p.pool.len() > 0 {
-		return p.pool.pop().SetUint64(0)
-	}
-	return new(big.Int)
-}
-
-// put returns an allocated big int to the pool to be later reused by get calls.
-// Note, the values as saved as is; neither put nor get zeroes the ints out!
-func (p *intPool) put(is ...*big.Int) {
-	if len(p.pool.data) > poolLimit {
-		return
-	}
-	for _, i := range is {
-		// verifyPool is a build flag. Pool verification makes sure the integrity
-		// of the integer pool by comparing values to a default value.
-		if verifyPool {
-			i.Set(checkVal)
-		}
-		p.pool.push(i)
-	}
-}
-
-// The intPool pool's default capacity
-const poolDefaultCap = 25
-
-// intPoolPool manages a pool of intPools.
-type intPoolPool struct {
-	pools []*intPool
-	lock  sync.Mutex
-}
-
-var poolOfIntPools = &intPoolPool{
-	pools: make([]*intPool, 0, poolDefaultCap),
-}
-
-// get is looking for an available pool to return.
-func (ipp *intPoolPool) get() *intPool {
-	ipp.lock.Lock()
-	defer ipp.lock.Unlock()
-
-	if len(poolOfIntPools.pools) > 0 {
-		ip := ipp.pools[len(ipp.pools)-1]
-		ipp.pools = ipp.pools[:len(ipp.pools)-1]
-		return ip
-	}
-	return newIntPool()
-}
-
-// put a pool that has been allocated with get.
-func (ipp *intPoolPool) put(ip *intPool) {
-	ipp.lock.Lock()
-	defer ipp.lock.Unlock()
-
-	if len(ipp.pools) < cap(ipp.pools) {
-		ipp.pools = append(ipp.pools, ip)
-	}
-}
diff --git a/core/vm/jump_table.go b/core/vm/jump_table.go
index 737dd14..7e3e354 100644
--- a/core/vm/jump_table.go
+++ b/core/vm/jump_table.go
@@ -17,20 +17,16 @@
 package vm
 
 import (
-	"errors"
-
 	"github.com/ava-labs/coreth/params"
 )
 
 type (
-	executionFunc func(pc *uint64, interpreter *EVMInterpreter, contract *Contract, memory *Memory, stack *Stack) ([]byte, error)
+	executionFunc func(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error)
 	gasFunc       func(*EVM, *Contract, *Stack, *Memory, uint64) (uint64, error) // last parameter is the requested memory size as a uint64
 	// memorySizeFunc returns the required size, and whether the operation overflowed a uint64
 	memorySizeFunc func(*Stack) (size uint64, overflow bool)
 )
 
-var errGasUintOverflow = errors.New("gas uint64 overflow")
-
 type operation struct {
 	// execute is the operation function
 	execute     executionFunc
@@ -48,7 +44,6 @@ type operation struct {
 	halts   bool // indicates whether the operation should halt further execution
 	jumps   bool // indicates whether the program counter should not increment
 	writes  bool // determines whether this a state modifying operation
-	valid   bool // indication whether the retrieved operation is valid and known
 	reverts bool // determines whether the operation reverts state (implicitly halts)
 	returns bool // determines whether the operations sets the return data content
 }
@@ -61,10 +56,19 @@ var (
 	byzantiumInstructionSet        = newByzantiumInstructionSet()
 	constantinopleInstructionSet   = newConstantinopleInstructionSet()
 	istanbulInstructionSet         = newIstanbulInstructionSet()
+	yoloV1InstructionSet           = newYoloV1InstructionSet()
 )
 
 // JumpTable contains the EVM opcodes supported at a given fork.
-type JumpTable [256]operation
+type JumpTable [256]*operation
+
+func newYoloV1InstructionSet() JumpTable {
+	instructionSet := newIstanbulInstructionSet()
+
+	enable2315(&instructionSet) // Subroutines - https://eips.ethereum.org/EIPS/eip-2315
+
+	return instructionSet
+}
 
 // newIstanbulInstructionSet returns the frontier, homestead
 // byzantium, contantinople and petersburg instructions.
@@ -82,42 +86,37 @@ func newIstanbulInstructionSet() JumpTable {
 // byzantium and contantinople instructions.
 func newConstantinopleInstructionSet() JumpTable {
 	instructionSet := newByzantiumInstructionSet()
-	instructionSet[SHL] = operation{
+	instructionSet[SHL] = &operation{
 		execute:     opSHL,
 		constantGas: GasFastestStep,
 		minStack:    minStack(2, 1),
 		maxStack:    maxStack(2, 1),
-		valid:       true,
 	}
-	instructionSet[SHR] = operation{
+	instructionSet[SHR] = &operation{
 		execute:     opSHR,
 		constantGas: GasFastestStep,
 		minStack:    minStack(2, 1),
 		maxStack:    maxStack(2, 1),
-		valid:       true,
 	}
-	instructionSet[SAR] = operation{
+	instructionSet[SAR] = &operation{
 		execute:     opSAR,
 		constantGas: GasFastestStep,
 		minStack:    minStack(2, 1),
 		maxStack:    maxStack(2, 1),
-		valid:       true,
 	}
-	instructionSet[EXTCODEHASH] = operation{
+	instructionSet[EXTCODEHASH] = &operation{
 		execute:     opExtCodeHash,
 		constantGas: params.ExtcodeHashGasConstantinople,
 		minStack:    minStack(1, 1),
 		maxStack:    maxStack(1, 1),
-		valid:       true,
 	}
-	instructionSet[CREATE2] = operation{
+	instructionSet[CREATE2] = &operation{
 		execute:     opCreate2,
 		constantGas: params.Create2Gas,
 		dynamicGas:  gasCreate2,
 		minStack:    minStack(4, 1),
 		maxStack:    maxStack(4, 1),
 		memorySize:  memoryCreate2,
-		valid:       true,
 		writes:      true,
 		returns:     true,
 	}
@@ -128,39 +127,35 @@ func newConstantinopleInstructionSet() JumpTable {
 // byzantium instructions.
 func newByzantiumInstructionSet() JumpTable {
 	instructionSet := newSpuriousDragonInstructionSet()
-	instructionSet[STATICCALL] = operation{
+	instructionSet[STATICCALL] = &operation{
 		execute:     opStaticCall,
 		constantGas: params.CallGasEIP150,
 		dynamicGas:  gasStaticCall,
 		minStack:    minStack(6, 1),
 		maxStack:    maxStack(6, 1),
 		memorySize:  memoryStaticCall,
-		valid:       true,
 		returns:     true,
 	}
-	instructionSet[RETURNDATASIZE] = operation{
+	instructionSet[RETURNDATASIZE] = &operation{
 		execute:     opReturnDataSize,
 		constantGas: GasQuickStep,
 		minStack:    minStack(0, 1),
 		maxStack:    maxStack(0, 1),
-		valid:       true,
 	}
-	instructionSet[RETURNDATACOPY] = operation{
+	instructionSet[RETURNDATACOPY] = &operation{
 		execute:     opReturnDataCopy,
 		constantGas: GasFastestStep,
 		dynamicGas:  gasReturnDataCopy,
 		minStack:    minStack(3, 0),
 		maxStack:    maxStack(3, 0),
 		memorySize:  memoryReturnDataCopy,
-		valid:       true,
 	}
-	instructionSet[REVERT] = operation{
+	instructionSet[REVERT] = &operation{
 		execute:    opRevert,
 		dynamicGas: gasRevert,
 		minStack:   minStack(2, 0),
 		maxStack:   maxStack(2, 0),
 		memorySize: memoryRevert,
-		valid:      true,
 		reverts:    true,
 		returns:    true,
 	}
@@ -193,14 +188,13 @@ func newTangerineWhistleInstructionSet() JumpTable {
 // instructions that can be executed during the homestead phase.
 func newHomesteadInstructionSet() JumpTable {
 	instructionSet := newFrontierInstructionSet()
-	instructionSet[DELEGATECALL] = operation{
+	instructionSet[DELEGATECALL] = &operation{
 		execute:     opDelegateCall,
 		dynamicGas:  gasDelegateCall,
 		constantGas: params.CallGasFrontier,
 		minStack:    minStack(6, 1),
 		maxStack:    maxStack(6, 1),
 		memorySize:  memoryDelegateCall,
-		valid:       true,
 		returns:     true,
 	}
 	return instructionSet
@@ -216,161 +210,138 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:    minStack(0, 0),
 			maxStack:    maxStack(0, 0),
 			halts:       true,
-			valid:       true,
 		},
 		ADD: {
 			execute:     opAdd,
 			constantGas: GasFastestStep,
 			minStack:    minStack(2, 1),
 			maxStack:    maxStack(2, 1),
-			valid:       true,
 		},
 		MUL: {
 			execute:     opMul,
 			constantGas: GasFastStep,
 			minStack:    minStack(2, 1),
 			maxStack:    maxStack(2, 1),
-			valid:       true,
 		},
 		SUB: {
 			execute:     opSub,
 			constantGas: GasFastestStep,
 			minStack:    minStack(2, 1),
 			maxStack:    maxStack(2, 1),
-			valid:       true,
 		},
 		DIV: {
 			execute:     opDiv,
 			constantGas: GasFastStep,
 			minStack:    minStack(2, 1),
 			maxStack:    maxStack(2, 1),
-			valid:       true,
 		},
 		SDIV: {
 			execute:     opSdiv,
 			constantGas: GasFastStep,
 			minStack:    minStack(2, 1),
 			maxStack:    maxStack(2, 1),
-			valid:       true,
 		},
 		MOD: {
 			execute:     opMod,
 			constantGas: GasFastStep,
 			minStack:    minStack(2, 1),
 			maxStack:    maxStack(2, 1),
-			valid:       true,
 		},
 		SMOD: {
 			execute:     opSmod,
 			constantGas: GasFastStep,
 			minStack:    minStack(2, 1),
 			maxStack:    maxStack(2, 1),
-			valid:       true,
 		},
 		ADDMOD: {
 			execute:     opAddmod,
 			constantGas: GasMidStep,
 			minStack:    minStack(3, 1),
 			maxStack:    maxStack(3, 1),
-			valid:       true,
 		},
 		MULMOD: {
 			execute:     opMulmod,
 			constantGas: GasMidStep,
 			minStack:    minStack(3, 1),
 			maxStack:    maxStack(3, 1),
-			valid:       true,
 		},
 		EXP: {
 			execute:    opExp,
 			dynamicGas: gasExpFrontier,
 			minStack:   minStack(2, 1),
 			maxStack:   maxStack(2, 1),
-			valid:      true,
 		},
 		SIGNEXTEND: {
 			execute:     opSignExtend,
 			constantGas: GasFastStep,
 			minStack:    minStack(2, 1),
 			maxStack:    maxStack(2, 1),
-			valid:       true,
 		},
 		LT: {
 			execute:     opLt,
 			constantGas: GasFastestStep,
 			minStack:    minStack(2, 1),
 			maxStack:    maxStack(2, 1),
-			valid:       true,
 		},
 		GT: {
 			execute:     opGt,
 			constantGas: GasFastestStep,
 			minStack:    minStack(2, 1),
 			maxStack:    maxStack(2, 1),
-			valid:       true,
 		},
 		SLT: {
 			execute:     opSlt,
 			constantGas: GasFastestStep,
 			minStack:    minStack(2, 1),
 			maxStack:    maxStack(2, 1),
-			valid:       true,
 		},
 		SGT: {
 			execute:     opSgt,
 			constantGas: GasFastestStep,
 			minStack:    minStack(2, 1),
 			maxStack:    maxStack(2, 1),
-			valid:       true,
 		},
 		EQ: {
 			execute:     opEq,
 			constantGas: GasFastestStep,
 			minStack:    minStack(2, 1),
 			maxStack:    maxStack(2, 1),
-			valid:       true,
 		},
 		ISZERO: {
 			execute:     opIszero,
 			constantGas: GasFastestStep,
 			minStack:    minStack(1, 1),
 			maxStack:    maxStack(1, 1),
-			valid:       true,
 		},
 		AND: {
 			execute:     opAnd,
 			constantGas: GasFastestStep,
 			minStack:    minStack(2, 1),
 			maxStack:    maxStack(2, 1),
-			valid:       true,
 		},
 		XOR: {
 			execute:     opXor,
 			constantGas: GasFastestStep,
 			minStack:    minStack(2, 1),
 			maxStack:    maxStack(2, 1),
-			valid:       true,
 		},
 		OR: {
 			execute:     opOr,
 			constantGas: GasFastestStep,
 			minStack:    minStack(2, 1),
 			maxStack:    maxStack(2, 1),
-			valid:       true,
 		},
 		NOT: {
 			execute:     opNot,
 			constantGas: GasFastestStep,
 			minStack:    minStack(1, 1),
 			maxStack:    maxStack(1, 1),
-			valid:       true,
 		},
 		BYTE: {
 			execute:     opByte,
 			constantGas: GasFastestStep,
 			minStack:    minStack(2, 1),
 			maxStack:    maxStack(2, 1),
-			valid:       true,
 		},
 		SHA3: {
 			execute:     opSha3,
@@ -379,63 +350,54 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:    minStack(2, 1),
 			maxStack:    maxStack(2, 1),
 			memorySize:  memorySha3,
-			valid:       true,
 		},
 		ADDRESS: {
 			execute:     opAddress,
 			constantGas: GasQuickStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		BALANCE: {
 			execute:     opBalance,
 			constantGas: params.BalanceGasFrontier,
 			minStack:    minStack(1, 1),
 			maxStack:    maxStack(1, 1),
-			valid:       true,
 		},
 		BALANCEMC: {
 			execute:     opBalanceMultiCoin,
 			constantGas: params.BalanceGasFrontier,
 			minStack:    minStack(2, 1),
 			maxStack:    maxStack(2, 1),
-			valid:       true,
 		},
 		ORIGIN: {
 			execute:     opOrigin,
 			constantGas: GasQuickStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		CALLER: {
 			execute:     opCaller,
 			constantGas: GasQuickStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		CALLVALUE: {
 			execute:     opCallValue,
 			constantGas: GasQuickStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		CALLDATALOAD: {
 			execute:     opCallDataLoad,
 			constantGas: GasFastestStep,
 			minStack:    minStack(1, 1),
 			maxStack:    maxStack(1, 1),
-			valid:       true,
 		},
 		CALLDATASIZE: {
 			execute:     opCallDataSize,
 			constantGas: GasQuickStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		CALLDATACOPY: {
 			execute:     opCallDataCopy,
@@ -444,14 +406,12 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:    minStack(3, 0),
 			maxStack:    maxStack(3, 0),
 			memorySize:  memoryCallDataCopy,
-			valid:       true,
 		},
 		CODESIZE: {
 			execute:     opCodeSize,
 			constantGas: GasQuickStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		CODECOPY: {
 			execute:     opCodeCopy,
@@ -460,21 +420,18 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:    minStack(3, 0),
 			maxStack:    maxStack(3, 0),
 			memorySize:  memoryCodeCopy,
-			valid:       true,
 		},
 		GASPRICE: {
 			execute:     opGasprice,
 			constantGas: GasQuickStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		EXTCODESIZE: {
 			execute:     opExtCodeSize,
 			constantGas: params.ExtcodeSizeGasFrontier,
 			minStack:    minStack(1, 1),
 			maxStack:    maxStack(1, 1),
-			valid:       true,
 		},
 		EXTCODECOPY: {
 			execute:     opExtCodeCopy,
@@ -483,56 +440,48 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:    minStack(4, 0),
 			maxStack:    maxStack(4, 0),
 			memorySize:  memoryExtCodeCopy,
-			valid:       true,
 		},
 		BLOCKHASH: {
 			execute:     opBlockhash,
 			constantGas: GasExtStep,
 			minStack:    minStack(1, 1),
 			maxStack:    maxStack(1, 1),
-			valid:       true,
 		},
 		COINBASE: {
 			execute:     opCoinbase,
 			constantGas: GasQuickStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		TIMESTAMP: {
 			execute:     opTimestamp,
 			constantGas: GasQuickStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		NUMBER: {
 			execute:     opNumber,
 			constantGas: GasQuickStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		DIFFICULTY: {
 			execute:     opDifficulty,
 			constantGas: GasQuickStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		GASLIMIT: {
 			execute:     opGasLimit,
 			constantGas: GasQuickStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		POP: {
 			execute:     opPop,
 			constantGas: GasQuickStep,
 			minStack:    minStack(1, 0),
 			maxStack:    maxStack(1, 0),
-			valid:       true,
 		},
 		MLOAD: {
 			execute:     opMload,
@@ -541,7 +490,6 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:    minStack(1, 1),
 			maxStack:    maxStack(1, 1),
 			memorySize:  memoryMLoad,
-			valid:       true,
 		},
 		MSTORE: {
 			execute:     opMstore,
@@ -550,7 +498,6 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:    minStack(2, 0),
 			maxStack:    maxStack(2, 0),
 			memorySize:  memoryMStore,
-			valid:       true,
 		},
 		MSTORE8: {
 			execute:     opMstore8,
@@ -559,22 +506,18 @@ func newFrontierInstructionSet() JumpTable {
 			memorySize:  memoryMStore8,
 			minStack:    minStack(2, 0),
 			maxStack:    maxStack(2, 0),
-
-			valid: true,
 		},
 		SLOAD: {
 			execute:     opSload,
 			constantGas: params.SloadGasFrontier,
 			minStack:    minStack(1, 1),
 			maxStack:    maxStack(1, 1),
-			valid:       true,
 		},
 		SSTORE: {
 			execute:    opSstore,
 			dynamicGas: gasSStore,
 			minStack:   minStack(2, 0),
 			maxStack:   maxStack(2, 0),
-			valid:      true,
 			writes:     true,
 		},
 		JUMP: {
@@ -583,7 +526,6 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:    minStack(1, 0),
 			maxStack:    maxStack(1, 0),
 			jumps:       true,
-			valid:       true,
 		},
 		JUMPI: {
 			execute:     opJumpi,
@@ -591,490 +533,420 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:    minStack(2, 0),
 			maxStack:    maxStack(2, 0),
 			jumps:       true,
-			valid:       true,
 		},
 		PC: {
 			execute:     opPc,
 			constantGas: GasQuickStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		MSIZE: {
 			execute:     opMsize,
 			constantGas: GasQuickStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		GAS: {
 			execute:     opGas,
 			constantGas: GasQuickStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		JUMPDEST: {
 			execute:     opJumpdest,
 			constantGas: params.JumpdestGas,
 			minStack:    minStack(0, 0),
 			maxStack:    maxStack(0, 0),
-			valid:       true,
 		},
 		EMC: {
 			execute:     opEMC,
 			constantGas: params.EMCGas,
 			minStack:    minStack(0, 0),
 			maxStack:    maxStack(0, 0),
-			valid:       true,
 		},
 		PUSH1: {
 			execute:     opPush1,
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH2: {
 			execute:     makePush(2, 2),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH3: {
 			execute:     makePush(3, 3),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH4: {
 			execute:     makePush(4, 4),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH5: {
 			execute:     makePush(5, 5),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH6: {
 			execute:     makePush(6, 6),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH7: {
 			execute:     makePush(7, 7),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH8: {
 			execute:     makePush(8, 8),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH9: {
 			execute:     makePush(9, 9),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH10: {
 			execute:     makePush(10, 10),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH11: {
 			execute:     makePush(11, 11),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH12: {
 			execute:     makePush(12, 12),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH13: {
 			execute:     makePush(13, 13),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH14: {
 			execute:     makePush(14, 14),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH15: {
 			execute:     makePush(15, 15),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH16: {
 			execute:     makePush(16, 16),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH17: {
 			execute:     makePush(17, 17),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH18: {
 			execute:     makePush(18, 18),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH19: {
 			execute:     makePush(19, 19),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH20: {
 			execute:     makePush(20, 20),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH21: {
 			execute:     makePush(21, 21),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH22: {
 			execute:     makePush(22, 22),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH23: {
 			execute:     makePush(23, 23),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH24: {
 			execute:     makePush(24, 24),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH25: {
 			execute:     makePush(25, 25),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH26: {
 			execute:     makePush(26, 26),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH27: {
 			execute:     makePush(27, 27),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH28: {
 			execute:     makePush(28, 28),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH29: {
 			execute:     makePush(29, 29),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH30: {
 			execute:     makePush(30, 30),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH31: {
 			execute:     makePush(31, 31),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		PUSH32: {
 			execute:     makePush(32, 32),
 			constantGas: GasFastestStep,
 			minStack:    minStack(0, 1),
 			maxStack:    maxStack(0, 1),
-			valid:       true,
 		},
 		DUP1: {
 			execute:     makeDup(1),
 			constantGas: GasFastestStep,
 			minStack:    minDupStack(1),
 			maxStack:    maxDupStack(1),
-			valid:       true,
 		},
 		DUP2: {
 			execute:     makeDup(2),
 			constantGas: GasFastestStep,
 			minStack:    minDupStack(2),
 			maxStack:    maxDupStack(2),
-			valid:       true,
 		},
 		DUP3: {
 			execute:     makeDup(3),
 			constantGas: GasFastestStep,
 			minStack:    minDupStack(3),
 			maxStack:    maxDupStack(3),
-			valid:       true,
 		},
 		DUP4: {
 			execute:     makeDup(4),
 			constantGas: GasFastestStep,
 			minStack:    minDupStack(4),
 			maxStack:    maxDupStack(4),
-			valid:       true,
 		},
 		DUP5: {
 			execute:     makeDup(5),
 			constantGas: GasFastestStep,
 			minStack:    minDupStack(5),
 			maxStack:    maxDupStack(5),
-			valid:       true,
 		},
 		DUP6: {
 			execute:     makeDup(6),
 			constantGas: GasFastestStep,
 			minStack:    minDupStack(6),
 			maxStack:    maxDupStack(6),
-			valid:       true,
 		},
 		DUP7: {
 			execute:     makeDup(7),
 			constantGas: GasFastestStep,
 			minStack:    minDupStack(7),
 			maxStack:    maxDupStack(7),
-			valid:       true,
 		},
 		DUP8: {
 			execute:     makeDup(8),
 			constantGas: GasFastestStep,
 			minStack:    minDupStack(8),
 			maxStack:    maxDupStack(8),
-			valid:       true,
 		},
 		DUP9: {
 			execute:     makeDup(9),
 			constantGas: GasFastestStep,
 			minStack:    minDupStack(9),
 			maxStack:    maxDupStack(9),
-			valid:       true,
 		},
 		DUP10: {
 			execute:     makeDup(10),
 			constantGas: GasFastestStep,
 			minStack:    minDupStack(10),
 			maxStack:    maxDupStack(10),
-			valid:       true,
 		},
 		DUP11: {
 			execute:     makeDup(11),
 			constantGas: GasFastestStep,
 			minStack:    minDupStack(11),
 			maxStack:    maxDupStack(11),
-			valid:       true,
 		},
 		DUP12: {
 			execute:     makeDup(12),
 			constantGas: GasFastestStep,
 			minStack:    minDupStack(12),
 			maxStack:    maxDupStack(12),
-			valid:       true,
 		},
 		DUP13: {
 			execute:     makeDup(13),
 			constantGas: GasFastestStep,
 			minStack:    minDupStack(13),
 			maxStack:    maxDupStack(13),
-			valid:       true,
 		},
 		DUP14: {
 			execute:     makeDup(14),
 			constantGas: GasFastestStep,
 			minStack:    minDupStack(14),
 			maxStack:    maxDupStack(14),
-			valid:       true,
 		},
 		DUP15: {
 			execute:     makeDup(15),
 			constantGas: GasFastestStep,
 			minStack:    minDupStack(15),
 			maxStack:    maxDupStack(15),
-			valid:       true,
 		},
 		DUP16: {
 			execute:     makeDup(16),
 			constantGas: GasFastestStep,
 			minStack:    minDupStack(16),
 			maxStack:    maxDupStack(16),
-			valid:       true,
 		},
 		SWAP1: {
 			execute:     makeSwap(1),
 			constantGas: GasFastestStep,
 			minStack:    minSwapStack(2),
 			maxStack:    maxSwapStack(2),
-			valid:       true,
 		},
 		SWAP2: {
 			execute:     makeSwap(2),
 			constantGas: GasFastestStep,
 			minStack:    minSwapStack(3),
 			maxStack:    maxSwapStack(3),
-			valid:       true,
 		},
 		SWAP3: {
 			execute:     makeSwap(3),
 			constantGas: GasFastestStep,
 			minStack:    minSwapStack(4),
 			maxStack:    maxSwapStack(4),
-			valid:       true,
 		},
 		SWAP4: {
 			execute:     makeSwap(4),
 			constantGas: GasFastestStep,
 			minStack:    minSwapStack(5),
 			maxStack:    maxSwapStack(5),
-			valid:       true,
 		},
 		SWAP5: {
 			execute:     makeSwap(5),
 			constantGas: GasFastestStep,
 			minStack:    minSwapStack(6),
 			maxStack:    maxSwapStack(6),
-			valid:       true,
 		},
 		SWAP6: {
 			execute:     makeSwap(6),
 			constantGas: GasFastestStep,
 			minStack:    minSwapStack(7),
 			maxStack:    maxSwapStack(7),
-			valid:       true,
 		},
 		SWAP7: {
 			execute:     makeSwap(7),
 			constantGas: GasFastestStep,
 			minStack:    minSwapStack(8),
 			maxStack:    maxSwapStack(8),
-			valid:       true,
 		},
 		SWAP8: {
 			execute:     makeSwap(8),
 			constantGas: GasFastestStep,
 			minStack:    minSwapStack(9),
 			maxStack:    maxSwapStack(9),
-			valid:       true,
 		},
 		SWAP9: {
 			execute:     makeSwap(9),
 			constantGas: GasFastestStep,
 			minStack:    minSwapStack(10),
 			maxStack:    maxSwapStack(10),
-			valid:       true,
 		},
 		SWAP10: {
 			execute:     makeSwap(10),
 			constantGas: GasFastestStep,
 			minStack:    minSwapStack(11),
 			maxStack:    maxSwapStack(11),
-			valid:       true,
 		},
 		SWAP11: {
 			execute:     makeSwap(11),
 			constantGas: GasFastestStep,
 			minStack:    minSwapStack(12),
 			maxStack:    maxSwapStack(12),
-			valid:       true,
 		},
 		SWAP12: {
 			execute:     makeSwap(12),
 			constantGas: GasFastestStep,
 			minStack:    minSwapStack(13),
 			maxStack:    maxSwapStack(13),
-			valid:       true,
 		},
 		SWAP13: {
 			execute:     makeSwap(13),
 			constantGas: GasFastestStep,
 			minStack:    minSwapStack(14),
 			maxStack:    maxSwapStack(14),
-			valid:       true,
 		},
 		SWAP14: {
 			execute:     makeSwap(14),
 			constantGas: GasFastestStep,
 			minStack:    minSwapStack(15),
 			maxStack:    maxSwapStack(15),
-			valid:       true,
 		},
 		SWAP15: {
 			execute:     makeSwap(15),
 			constantGas: GasFastestStep,
 			minStack:    minSwapStack(16),
 			maxStack:    maxSwapStack(16),
-			valid:       true,
 		},
 		SWAP16: {
 			execute:     makeSwap(16),
 			constantGas: GasFastestStep,
 			minStack:    minSwapStack(17),
 			maxStack:    maxSwapStack(17),
-			valid:       true,
 		},
 		LOG0: {
 			execute:    makeLog(0),
@@ -1082,7 +954,6 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:   minStack(2, 0),
 			maxStack:   maxStack(2, 0),
 			memorySize: memoryLog,
-			valid:      true,
 			writes:     true,
 		},
 		LOG1: {
@@ -1091,7 +962,6 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:   minStack(3, 0),
 			maxStack:   maxStack(3, 0),
 			memorySize: memoryLog,
-			valid:      true,
 			writes:     true,
 		},
 		LOG2: {
@@ -1100,7 +970,6 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:   minStack(4, 0),
 			maxStack:   maxStack(4, 0),
 			memorySize: memoryLog,
-			valid:      true,
 			writes:     true,
 		},
 		LOG3: {
@@ -1109,7 +978,6 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:   minStack(5, 0),
 			maxStack:   maxStack(5, 0),
 			memorySize: memoryLog,
-			valid:      true,
 			writes:     true,
 		},
 		LOG4: {
@@ -1118,7 +986,6 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:   minStack(6, 0),
 			maxStack:   maxStack(6, 0),
 			memorySize: memoryLog,
-			valid:      true,
 			writes:     true,
 		},
 		CREATE: {
@@ -1128,7 +995,6 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:    minStack(3, 1),
 			maxStack:    maxStack(3, 1),
 			memorySize:  memoryCreate,
-			valid:       true,
 			writes:      true,
 			returns:     true,
 		},
@@ -1139,7 +1005,6 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:    minStack(7, 1),
 			maxStack:    maxStack(7, 1),
 			memorySize:  memoryCall,
-			valid:       true,
 			returns:     true,
 		},
 		CALLEX: {
@@ -1149,7 +1014,6 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:    minStack(9, 1),
 			maxStack:    maxStack(9, 1),
 			memorySize:  memoryCallExpert,
-			valid:       true,
 			returns:     true,
 		},
 		CALLCODE: {
@@ -1159,7 +1023,6 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:    minStack(7, 1),
 			maxStack:    maxStack(7, 1),
 			memorySize:  memoryCall,
-			valid:       true,
 			returns:     true,
 		},
 		RETURN: {
@@ -1169,7 +1032,6 @@ func newFrontierInstructionSet() JumpTable {
 			maxStack:   maxStack(2, 0),
 			memorySize: memoryReturn,
 			halts:      true,
-			valid:      true,
 		},
 		SELFDESTRUCT: {
 			execute:    opSuicide,
@@ -1177,7 +1039,6 @@ func newFrontierInstructionSet() JumpTable {
 			minStack:   minStack(1, 0),
 			maxStack:   maxStack(1, 0),
 			halts:      true,
-			valid:      true,
 			writes:     true,
 		},
 	}
diff --git a/core/vm/logger.go b/core/vm/logger.go
index 95143f1..ea5d6f2 100644
--- a/core/vm/logger.go
+++ b/core/vm/logger.go
@@ -18,17 +18,21 @@ package vm
 
 import (
 	"encoding/hex"
+	"errors"
 	"fmt"
 	"io"
 	"math/big"
+	"strings"
 	"time"
 
 	"github.com/ava-labs/coreth/core/types"
-	"github.com/ava-labs/go-ethereum/common"
-	"github.com/ava-labs/go-ethereum/common/hexutil"
-	"github.com/ava-labs/go-ethereum/common/math"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/common/math"
 )
 
+var errTraceLimitReached = errors.New("the number of logs reached the specified limit")
+
 // Storage represents a contract's storage.
 type Storage map[common.Hash]common.Hash
 
@@ -38,17 +42,17 @@ func (s Storage) Copy() Storage {
 	for key, value := range s {
 		cpy[key] = value
 	}
-
 	return cpy
 }
 
 // LogConfig are the configuration options for structured logger the EVM
 type LogConfig struct {
-	DisableMemory  bool // disable memory capture
-	DisableStack   bool // disable stack capture
-	DisableStorage bool // disable storage capture
-	Debug          bool // print output during capture end
-	Limit          int  // maximum length of output, but zero means unlimited
+	DisableMemory     bool // disable memory capture
+	DisableStack      bool // disable stack capture
+	DisableStorage    bool // disable storage capture
+	DisableReturnData bool // disable return data capture
+	Debug             bool // print output during capture end
+	Limit             int  // maximum length of output, but zero means unlimited
 }
 
 //go:generate gencodec -type StructLog -field-override structLogMarshaling -out gen_structlog.go
@@ -63,6 +67,8 @@ type StructLog struct {
 	Memory        []byte                      `json:"memory"`
 	MemorySize    int                         `json:"memSize"`
 	Stack         []*big.Int                  `json:"stack"`
+	ReturnStack   []uint32                    `json:"returnStack"`
+	ReturnData    []byte                      `json:"returnData"`
 	Storage       map[common.Hash]common.Hash `json:"-"`
 	Depth         int                         `json:"depth"`
 	RefundCounter uint64                      `json:"refund"`
@@ -72,6 +78,7 @@ type StructLog struct {
 // overrides for gencodec
 type structLogMarshaling struct {
 	Stack       []*math.HexOrDecimal256
+	ReturnStack []math.HexOrDecimal64
 	Gas         math.HexOrDecimal64
 	GasCost     math.HexOrDecimal64
 	Memory      hexutil.Bytes
@@ -98,9 +105,9 @@ func (s *StructLog) ErrorString() string {
 // Note that reference types are actual VM data structures; make copies
 // if you need to retain them beyond the current call.
 type Tracer interface {
-	CaptureStart(from common.Address, to common.Address, call bool, input []byte, gas uint64, value *big.Int) error
-	CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, contract *Contract, depth int, err error) error
-	CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, contract *Contract, depth int, err error) error
+	CaptureStart(from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) error
+	CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, rStack *ReturnStack, rData []byte, contract *Contract, depth int, err error) error
+	CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, rStack *ReturnStack, contract *Contract, depth int, err error) error
 	CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) error
 }
 
@@ -112,16 +119,16 @@ type Tracer interface {
 type StructLogger struct {
 	cfg LogConfig
 
-	logs          []StructLog
-	changedValues map[common.Address]Storage
-	output        []byte
-	err           error
+	storage map[common.Address]Storage
+	logs    []StructLog
+	output  []byte
+	err     error
 }
 
 // NewStructLogger returns a new logger
 func NewStructLogger(cfg *LogConfig) *StructLogger {
 	logger := &StructLogger{
-		changedValues: make(map[common.Address]Storage),
+		storage: make(map[common.Address]Storage),
 	}
 	if cfg != nil {
 		logger.cfg = *cfg
@@ -136,27 +143,11 @@ func (l *StructLogger) CaptureStart(from common.Address, to common.Address, crea
 
 // CaptureState logs a new structured log message and pushes it out to the environment
 //
-// CaptureState also tracks SSTORE ops to track dirty values.
-func (l *StructLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, contract *Contract, depth int, err error) error {
+// CaptureState also tracks SLOAD/SSTORE ops to track storage change.
+func (l *StructLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, rStack *ReturnStack, rData []byte, contract *Contract, depth int, err error) error {
 	// check if already accumulated the specified number of logs
 	if l.cfg.Limit != 0 && l.cfg.Limit <= len(l.logs) {
-		return ErrTraceLimitReached
-	}
-
-	// initialise new changed values storage container for this contract
-	// if not present.
-	if l.changedValues[contract.Address()] == nil {
-		l.changedValues[contract.Address()] = make(Storage)
-	}
-
-	// capture SSTORE opcodes and determine the changed value and store
-	// it in the local storage container.
-	if op == SSTORE && stack.len() >= 2 {
-		var (
-			value   = common.BigToHash(stack.data[stack.len()-2])
-			address = common.BigToHash(stack.data[stack.len()-1])
-		)
-		l.changedValues[contract.Address()][address] = value
+		return errTraceLimitReached
 	}
 	// Copy a snapshot of the current memory state to a new buffer
 	var mem []byte
@@ -169,24 +160,54 @@ func (l *StructLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost ui
 	if !l.cfg.DisableStack {
 		stck = make([]*big.Int, len(stack.Data()))
 		for i, item := range stack.Data() {
-			stck[i] = new(big.Int).Set(item)
+			stck[i] = new(big.Int).Set(item.ToBig())
 		}
 	}
+	var rstack []uint32
+	if !l.cfg.DisableStack && rStack != nil {
+		rstck := make([]uint32, len(rStack.data))
+		copy(rstck, rStack.data)
+	}
 	// Copy a snapshot of the current storage to a new container
 	var storage Storage
 	if !l.cfg.DisableStorage {
-		storage = l.changedValues[contract.Address()].Copy()
+		// initialise new changed values storage container for this contract
+		// if not present.
+		if l.storage[contract.Address()] == nil {
+			l.storage[contract.Address()] = make(Storage)
+		}
+		// capture SLOAD opcodes and record the read entry in the local storage
+		if op == SLOAD && stack.len() >= 1 {
+			var (
+				address = common.Hash(stack.data[stack.len()-1].Bytes32())
+				value   = env.StateDB.GetState(contract.Address(), address)
+			)
+			l.storage[contract.Address()][address] = value
+		}
+		// capture SSTORE opcodes and record the written entry in the local storage.
+		if op == SSTORE && stack.len() >= 2 {
+			var (
+				value   = common.Hash(stack.data[stack.len()-2].Bytes32())
+				address = common.Hash(stack.data[stack.len()-1].Bytes32())
+			)
+			l.storage[contract.Address()][address] = value
+		}
+		storage = l.storage[contract.Address()].Copy()
+	}
+	var rdata []byte
+	if !l.cfg.DisableReturnData {
+		rdata = make([]byte, len(rData))
+		copy(rdata, rData)
 	}
 	// create a new snapshot of the EVM.
-	log := StructLog{pc, op, gas, cost, mem, memory.Len(), stck, storage, depth, env.StateDB.GetRefund(), err}
-
+	log := StructLog{pc, op, gas, cost, mem, memory.Len(), stck, rstack, rdata, storage, depth, env.StateDB.GetRefund(), err}
 	l.logs = append(l.logs, log)
 	return nil
 }
 
 // CaptureFault implements the Tracer interface to trace an execution fault
 // while running an opcode.
-func (l *StructLogger) CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, contract *Contract, depth int, err error) error {
+func (l *StructLogger) CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, rStack *ReturnStack, contract *Contract, depth int, err error) error {
 	return nil
 }
 
@@ -227,6 +248,12 @@ func WriteTrace(writer io.Writer, logs []StructLog) {
 				fmt.Fprintf(writer, "%08d  %x\n", len(log.Stack)-i-1, math.PaddedBigBytes(log.Stack[i], 32))
 			}
 		}
+		if len(log.ReturnStack) > 0 {
+			fmt.Fprintln(writer, "ReturnStack:")
+			for i := len(log.Stack) - 1; i >= 0; i-- {
+				fmt.Fprintf(writer, "%08d  0x%x (%d)\n", len(log.Stack)-i-1, log.ReturnStack[i], log.ReturnStack[i])
+			}
+		}
 		if len(log.Memory) > 0 {
 			fmt.Fprintln(writer, "Memory:")
 			fmt.Fprint(writer, hex.Dump(log.Memory))
@@ -237,6 +264,10 @@ func WriteTrace(writer io.Writer, logs []StructLog) {
 				fmt.Fprintf(writer, "%x: %x\n", h, item)
 			}
 		}
+		if len(log.ReturnData) > 0 {
+			fmt.Fprintln(writer, "ReturnData:")
+			fmt.Fprint(writer, hex.Dump(log.ReturnData))
+		}
 		fmt.Fprintln(writer)
 	}
 }
@@ -254,3 +285,79 @@ func WriteLogs(writer io.Writer, logs []*types.Log) {
 		fmt.Fprintln(writer)
 	}
 }
+
+type mdLogger struct {
+	out io.Writer
+	cfg *LogConfig
+}
+
+// NewMarkdownLogger creates a logger which outputs information in a format adapted
+// for human readability, and is also a valid markdown table
+func NewMarkdownLogger(cfg *LogConfig, writer io.Writer) *mdLogger {
+	l := &mdLogger{writer, cfg}
+	if l.cfg == nil {
+		l.cfg = &LogConfig{}
+	}
+	return l
+}
+
+func (t *mdLogger) CaptureStart(from common.Address, to common.Address, create bool, input []byte, gas uint64, value *big.Int) error {
+	if !create {
+		fmt.Fprintf(t.out, "From: `%v`\nTo: `%v`\nData: `0x%x`\nGas: `%d`\nValue `%v` wei\n",
+			from.String(), to.String(),
+			input, gas, value)
+	} else {
+		fmt.Fprintf(t.out, "From: `%v`\nCreate at: `%v`\nData: `0x%x`\nGas: `%d`\nValue `%v` wei\n",
+			from.String(), to.String(),
+			input, gas, value)
+	}
+
+	fmt.Fprintf(t.out, `
+|  Pc   |      Op     | Cost |   Stack   |   RStack  |
+|-------|-------------|------|-----------|-----------|
+`)
+	return nil
+}
+
+func (t *mdLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, rStack *ReturnStack, rData []byte, contract *Contract, depth int, err error) error {
+	fmt.Fprintf(t.out, "| %4d  | %10v  |  %3d |", pc, op, cost)
+
+	if !t.cfg.DisableStack { // format stack
+		var a []string
+		for _, elem := range stack.data {
+			a = append(a, fmt.Sprintf("%d", elem))
+		}
+		b := fmt.Sprintf("[%v]", strings.Join(a, ","))
+		fmt.Fprintf(t.out, "%10v |", b)
+	}
+	if !t.cfg.DisableStack { // format return stack
+		var a []string
+		for _, elem := range rStack.data {
+			a = append(a, fmt.Sprintf("%2d", elem))
+		}
+		b := fmt.Sprintf("[%v]", strings.Join(a, ","))
+		fmt.Fprintf(t.out, "%10v |", b)
+	}
+	fmt.Fprintln(t.out, "")
+	if err != nil {
+		fmt.Fprintf(t.out, "Error: %v\n", err)
+	}
+	return nil
+}
+
+func (t *mdLogger) CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, rStack *ReturnStack, contract *Contract, depth int, err error) error {
+
+	fmt.Fprintf(t.out, "\nError: at pc=%d, op=%v: %v\n", pc, op, err)
+
+	return nil
+}
+
+func (t *mdLogger) CaptureEnd(output []byte, gasUsed uint64, tm time.Duration, err error) error {
+	fmt.Fprintf(t.out, `
+Output: 0x%x
+Consumed gas: %d
+Error: %v
+`,
+		output, gasUsed, err)
+	return nil
+}
diff --git a/core/vm/logger_json.go b/core/vm/logger_json.go
index 5068343..5f3f2c4 100644
--- a/core/vm/logger_json.go
+++ b/core/vm/logger_json.go
@@ -22,8 +22,8 @@ import (
 	"math/big"
 	"time"
 
-	"github.com/ava-labs/go-ethereum/common"
-	"github.com/ava-labs/go-ethereum/common/math"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/math"
 )
 
 type JSONLogger struct {
@@ -46,7 +46,7 @@ func (l *JSONLogger) CaptureStart(from common.Address, to common.Address, create
 }
 
 // CaptureState outputs state information on the logger.
-func (l *JSONLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, contract *Contract, depth int, err error) error {
+func (l *JSONLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, rStack *ReturnStack, rData []byte, contract *Contract, depth int, err error) error {
 	log := StructLog{
 		Pc:            pc,
 		Op:            op,
@@ -62,13 +62,22 @@ func (l *JSONLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint
 		log.Memory = memory.Data()
 	}
 	if !l.cfg.DisableStack {
-		log.Stack = stack.Data()
+		//TODO(@holiman) improve this
+		logstack := make([]*big.Int, len(stack.Data()))
+		for i, item := range stack.Data() {
+			logstack[i] = item.ToBig()
+		}
+		log.Stack = logstack
+		log.ReturnStack = rStack.data
+	}
+	if !l.cfg.DisableReturnData {
+		log.ReturnData = rData
 	}
 	return l.encoder.Encode(log)
 }
 
 // CaptureFault outputs state information on the logger.
-func (l *JSONLogger) CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, contract *Contract, depth int, err error) error {
+func (l *JSONLogger) CaptureFault(env *EVM, pc uint64, op OpCode, gas, cost uint64, memory *Memory, stack *Stack, rStack *ReturnStack, contract *Contract, depth int, err error) error {
 	return nil
 }
 
diff --git a/core/vm/memory.go b/core/vm/memory.go
index 5408707..ba5f848 100644
--- a/core/vm/memory.go
+++ b/core/vm/memory.go
@@ -18,9 +18,8 @@ package vm
 
 import (
 	"fmt"
-	"math/big"
 
-	"github.com/ava-labs/go-ethereum/common/math"
+	"github.com/holiman/uint256"
 )
 
 // Memory implements a simple memory model for the ethereum virtual machine.
@@ -50,7 +49,7 @@ func (m *Memory) Set(offset, size uint64, value []byte) {
 
 // Set32 sets the 32 bytes starting at offset to the value of val, left-padded with zeroes to
 // 32 bytes.
-func (m *Memory) Set32(offset uint64, val *big.Int) {
+func (m *Memory) Set32(offset uint64, val *uint256.Int) {
 	// length of store may never be less than offset + size.
 	// The store should be resized PRIOR to setting the memory
 	if offset+32 > uint64(len(m.store)) {
@@ -59,7 +58,7 @@ func (m *Memory) Set32(offset uint64, val *big.Int) {
 	// Zero the memory area
 	copy(m.store[offset:offset+32], []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0})
 	// Fill in relevant bits
-	math.ReadBits(val, m.store[offset:offset+32])
+	val.WriteToSlice(m.store[offset:])
 }
 
 // Resize resizes the memory to size
@@ -70,7 +69,7 @@ func (m *Memory) Resize(size uint64) {
 }
 
 // Get returns offset + size as a new slice
-func (m *Memory) Get(offset, size int64) (cpy []byte) {
+func (m *Memory) GetCopy(offset, size int64) (cpy []byte) {
 	if size == 0 {
 		return nil
 	}
diff --git a/core/vm/opcodes.go b/core/vm/opcodes.go
index 1a66ef8..99688b1 100644
--- a/core/vm/opcodes.go
+++ b/core/vm/opcodes.go
@@ -70,7 +70,7 @@ const (
 	SHR
 	SAR
 
-	SHA3 = 0x20
+	SHA3 OpCode = 0x20
 )
 
 // 0x30 range - closure state.
@@ -101,26 +101,27 @@ const (
 	NUMBER
 	DIFFICULTY
 	GASLIMIT
-	CHAINID     = 0x46
-	SELFBALANCE = 0x47
+	CHAINID     OpCode = 0x46
+	SELFBALANCE OpCode = 0x47
 )
 
 // 0x50 range - 'storage' and execution.
 const (
-	POP OpCode = 0x50 + iota
-	MLOAD
-	MSTORE
-	MSTORE8
-	SLOAD
-	SSTORE
-	JUMP
-	JUMPI
-	PC
-	MSIZE
-	GAS
-	JUMPDEST
-	EMC       = 0x5c
-	BALANCEMC = 0x5d
+	POP       OpCode = 0x50
+	MLOAD     OpCode = 0x51
+	MSTORE    OpCode = 0x52
+	MSTORE8   OpCode = 0x53
+	SLOAD     OpCode = 0x54
+	SSTORE    OpCode = 0x55
+	JUMP      OpCode = 0x56
+	JUMPI     OpCode = 0x57
+	PC        OpCode = 0x58
+	MSIZE     OpCode = 0x59
+	GAS       OpCode = 0x5a
+	JUMPDEST  OpCode = 0x5b
+	BEGINSUB  OpCode = 0x5c
+	RETURNSUB OpCode = 0x5d
+	JUMPSUB   OpCode = 0x5e
 )
 
 // 0x60 range.
@@ -207,6 +208,12 @@ const (
 	SWAP
 )
 
+const (
+	BALANCEMC = 0xcd
+	EMC       = 0xce
+	CALLEX    = 0xcf
+)
+
 // 0xf0 range - closures.
 const (
 	CREATE OpCode = 0xf0 + iota
@@ -215,11 +222,9 @@ const (
 	RETURN
 	DELEGATECALL
 	CREATE2
-	CALLEX     = 0xf6
-	STATICCALL = 0xfa
-
-	REVERT       = 0xfd
-	SELFDESTRUCT = 0xff
+	STATICCALL   OpCode = 0xfa
+	REVERT       OpCode = 0xfd
+	SELFDESTRUCT OpCode = 0xff
 )
 
 // Since the opcodes aren't all in order we can't use a regular slice.
@@ -301,7 +306,10 @@ var opCodeToString = map[OpCode]string{
 	MSIZE:    "MSIZE",
 	GAS:      "GAS",
 	JUMPDEST: "JUMPDEST",
-	EMC:      "EMC",
+
+	BEGINSUB:  "BEGINSUB",
+	JUMPSUB:   "JUMPSUB",
+	RETURNSUB: "RETURNSUB",
 
 	// 0x60 range - push.
 	PUSH1:  "PUSH1",
@@ -379,6 +387,7 @@ var opCodeToString = map[OpCode]string{
 	// 0xf0 range.
 	CREATE:       "CREATE",
 	CALL:         "CALL",
+	EMC:          "EMC",
 	CALLEX:       "CALLEX",
 	RETURN:       "RETURN",
 	CALLCODE:     "CALLCODE",
@@ -396,7 +405,7 @@ var opCodeToString = map[OpCode]string{
 func (op OpCode) String() string {
 	str := opCodeToString[op]
 	if len(str) == 0 {
-		return fmt.Sprintf("Missing opcode 0x%x", int(op))
+		return fmt.Sprintf("opcode 0x%x not defined", int(op))
 	}
 
 	return str
@@ -469,7 +478,9 @@ var stringToOp = map[string]OpCode{
 	"MSIZE":          MSIZE,
 	"GAS":            GAS,
 	"JUMPDEST":       JUMPDEST,
-	"EMC":            EMC,
+	"BEGINSUB":       BEGINSUB,
+	"RETURNSUB":      RETURNSUB,
+	"JUMPSUB":        JUMPSUB,
 	"PUSH1":          PUSH1,
 	"PUSH2":          PUSH2,
 	"PUSH3":          PUSH3,
@@ -542,6 +553,7 @@ var stringToOp = map[string]OpCode{
 	"CREATE":         CREATE,
 	"CREATE2":        CREATE2,
 	"CALL":           CALL,
+	"EMC":            EMC,
 	"CALLEX":         CALLEX,
 	"RETURN":         RETURN,
 	"CALLCODE":       CALLCODE,
diff --git a/core/vm/stack.go b/core/vm/stack.go
index 4c1b9e8..af27d65 100644
--- a/core/vm/stack.go
+++ b/core/vm/stack.go
@@ -18,36 +18,48 @@ package vm
 
 import (
 	"fmt"
-	"math/big"
+	"sync"
+
+	"github.com/holiman/uint256"
 )
 
+var stackPool = sync.Pool{
+	New: func() interface{} {
+		return &Stack{data: make([]uint256.Int, 0, 16)}
+	},
+}
+
 // Stack is an object for basic stack operations. Items popped to the stack are
 // expected to be changed and modified. stack does not take care of adding newly
 // initialised objects.
 type Stack struct {
-	data []*big.Int
+	data []uint256.Int
 }
 
 func newstack() *Stack {
-	return &Stack{data: make([]*big.Int, 0, 1024)}
+	return stackPool.Get().(*Stack)
 }
 
-// Data returns the underlying big.Int array.
-func (st *Stack) Data() []*big.Int {
+func returnStack(s *Stack) {
+	s.data = s.data[:0]
+	stackPool.Put(s)
+}
+
+// Data returns the underlying uint256.Int array.
+func (st *Stack) Data() []uint256.Int {
 	return st.data
 }
 
-func (st *Stack) push(d *big.Int) {
+func (st *Stack) push(d *uint256.Int) {
 	// NOTE push limit (1024) is checked in baseCheck
-	//stackItem := new(big.Int).Set(d)
-	//st.data = append(st.data, stackItem)
-	st.data = append(st.data, d)
+	st.data = append(st.data, *d)
 }
-func (st *Stack) pushN(ds ...*big.Int) {
+func (st *Stack) pushN(ds ...uint256.Int) {
+	// FIXME: Is there a way to pass args by pointers.
 	st.data = append(st.data, ds...)
 }
 
-func (st *Stack) pop() (ret *big.Int) {
+func (st *Stack) pop() (ret uint256.Int) {
 	ret = st.data[len(st.data)-1]
 	st.data = st.data[:len(st.data)-1]
 	return
@@ -61,24 +73,17 @@ func (st *Stack) swap(n int) {
 	st.data[st.len()-n], st.data[st.len()-1] = st.data[st.len()-1], st.data[st.len()-n]
 }
 
-func (st *Stack) dup(pool *intPool, n int) {
-	st.push(pool.get().Set(st.data[st.len()-n]))
+func (st *Stack) dup(n int) {
+	st.push(&st.data[st.len()-n])
 }
 
-func (st *Stack) peek() *big.Int {
-	return st.data[st.len()-1]
+func (st *Stack) peek() *uint256.Int {
+	return &st.data[st.len()-1]
 }
 
 // Back returns the n'th item in stack
-func (st *Stack) Back(n int) *big.Int {
-	return st.data[st.len()-n-1]
-}
-
-func (st *Stack) require(n int) error {
-	if st.len() < n {
-		return fmt.Errorf("stack underflow (%d <=> %d)", len(st.data), n)
-	}
-	return nil
+func (st *Stack) Back(n int) *uint256.Int {
+	return &st.data[st.len()-n-1]
 }
 
 // Print dumps the content of the stack
@@ -93,3 +98,34 @@ func (st *Stack) Print() {
 	}
 	fmt.Println("#############")
 }
+
+var rStackPool = sync.Pool{
+	New: func() interface{} {
+		return &ReturnStack{data: make([]uint32, 0, 10)}
+	},
+}
+
+// ReturnStack is an object for basic return stack operations.
+type ReturnStack struct {
+	data []uint32
+}
+
+func newReturnStack() *ReturnStack {
+	return rStackPool.Get().(*ReturnStack)
+}
+
+func returnRStack(rs *ReturnStack) {
+	rs.data = rs.data[:0]
+	rStackPool.Put(rs)
+}
+
+func (st *ReturnStack) push(d uint32) {
+	st.data = append(st.data, d)
+}
+
+// A uint32 is sufficient as for code below 4.2G
+func (st *ReturnStack) pop() (ret uint32) {
+	ret = st.data[len(st.data)-1]
+	st.data = st.data[:len(st.data)-1]
+	return
+}