Add native asset precompiled contracts for apricot release

6 files changed, 245 insertions, 52 deletions

diff --git a/core/vm/contracts.go b/core/vm/contracts.go
index 9827bac..6fc6334 100644
--- a/core/vm/contracts.go
+++ b/core/vm/contracts.go
@@ -44,61 +44,61 @@ type PrecompiledContract interface {
 
 // PrecompiledContractsHomestead contains the default set of pre-compiled Ethereum
 // contracts used in the Frontier and Homestead releases.
-var PrecompiledContractsHomestead = map[common.Address]PrecompiledContract{
-	common.BytesToAddress([]byte{1}): &ecrecover{},
-	common.BytesToAddress([]byte{2}): &sha256hash{},
-	common.BytesToAddress([]byte{3}): &ripemd160hash{},
-	common.BytesToAddress([]byte{4}): &dataCopy{},
+var PrecompiledContractsHomestead = map[common.Address]StatefulPrecompiledContract{
+	common.BytesToAddress([]byte{1}): newWrappedPrecompiledContract(&ecrecover{}),
+	common.BytesToAddress([]byte{2}): newWrappedPrecompiledContract(&sha256hash{}),
+	common.BytesToAddress([]byte{3}): newWrappedPrecompiledContract(&ripemd160hash{}),
+	common.BytesToAddress([]byte{4}): newWrappedPrecompiledContract(&dataCopy{}),
 }
 
 // PrecompiledContractsByzantium contains the default set of pre-compiled Ethereum
 // contracts used in the Byzantium release.
-var PrecompiledContractsByzantium = 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}): &bn256AddByzantium{},
-	common.BytesToAddress([]byte{7}): &bn256ScalarMulByzantium{},
-	common.BytesToAddress([]byte{8}): &bn256PairingByzantium{},
+var PrecompiledContractsByzantium = map[common.Address]StatefulPrecompiledContract{
+	common.BytesToAddress([]byte{1}): newWrappedPrecompiledContract(&ecrecover{}),
+	common.BytesToAddress([]byte{2}): newWrappedPrecompiledContract(&sha256hash{}),
+	common.BytesToAddress([]byte{3}): newWrappedPrecompiledContract(&ripemd160hash{}),
+	common.BytesToAddress([]byte{4}): newWrappedPrecompiledContract(&dataCopy{}),
+	common.BytesToAddress([]byte{5}): newWrappedPrecompiledContract(&bigModExp{}),
+	common.BytesToAddress([]byte{6}): newWrappedPrecompiledContract(&bn256AddByzantium{}),
+	common.BytesToAddress([]byte{7}): newWrappedPrecompiledContract(&bn256ScalarMulByzantium{}),
+	common.BytesToAddress([]byte{8}): newWrappedPrecompiledContract(&bn256PairingByzantium{}),
 }
 
 // PrecompiledContractsIstanbul contains the default set of pre-compiled Ethereum
 // contracts used in the Istanbul release.
-var PrecompiledContractsIstanbul = 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{},
+var PrecompiledContractsIstanbul = map[common.Address]StatefulPrecompiledContract{
+	common.BytesToAddress([]byte{1}): newWrappedPrecompiledContract(&ecrecover{}),
+	common.BytesToAddress([]byte{2}): newWrappedPrecompiledContract(&sha256hash{}),
+	common.BytesToAddress([]byte{3}): newWrappedPrecompiledContract(&ripemd160hash{}),
+	common.BytesToAddress([]byte{4}): newWrappedPrecompiledContract(&dataCopy{}),
+	common.BytesToAddress([]byte{5}): newWrappedPrecompiledContract(&bigModExp{}),
+	common.BytesToAddress([]byte{6}): newWrappedPrecompiledContract(&bn256AddIstanbul{}),
+	common.BytesToAddress([]byte{7}): newWrappedPrecompiledContract(&bn256ScalarMulIstanbul{}),
+	common.BytesToAddress([]byte{8}): newWrappedPrecompiledContract(&bn256PairingIstanbul{}),
+	common.BytesToAddress([]byte{9}): newWrappedPrecompiledContract(&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{},
+var PrecompiledContractsYoloV1 = map[common.Address]StatefulPrecompiledContract{
+	common.BytesToAddress([]byte{1}):  newWrappedPrecompiledContract(&ecrecover{}),
+	common.BytesToAddress([]byte{2}):  newWrappedPrecompiledContract(&sha256hash{}),
+	common.BytesToAddress([]byte{3}):  newWrappedPrecompiledContract(&ripemd160hash{}),
+	common.BytesToAddress([]byte{4}):  newWrappedPrecompiledContract(&dataCopy{}),
+	common.BytesToAddress([]byte{5}):  newWrappedPrecompiledContract(&bigModExp{}),
+	common.BytesToAddress([]byte{6}):  newWrappedPrecompiledContract(&bn256AddIstanbul{}),
+	common.BytesToAddress([]byte{7}):  newWrappedPrecompiledContract(&bn256ScalarMulIstanbul{}),
+	common.BytesToAddress([]byte{8}):  newWrappedPrecompiledContract(&bn256PairingIstanbul{}),
+	common.BytesToAddress([]byte{9}):  newWrappedPrecompiledContract(&blake2F{}),
+	common.BytesToAddress([]byte{10}): newWrappedPrecompiledContract(&bls12381G1Add{}),
+	common.BytesToAddress([]byte{11}): newWrappedPrecompiledContract(&bls12381G1Mul{}),
+	common.BytesToAddress([]byte{12}): newWrappedPrecompiledContract(&bls12381G1MultiExp{}),
+	common.BytesToAddress([]byte{13}): newWrappedPrecompiledContract(&bls12381G2Add{}),
+	common.BytesToAddress([]byte{14}): newWrappedPrecompiledContract(&bls12381G2Mul{}),
+	common.BytesToAddress([]byte{15}): newWrappedPrecompiledContract(&bls12381G2MultiExp{}),
+	common.BytesToAddress([]byte{16}): newWrappedPrecompiledContract(&bls12381Pairing{}),
+	common.BytesToAddress([]byte{17}): newWrappedPrecompiledContract(&bls12381MapG1{}),
+	common.BytesToAddress([]byte{18}): newWrappedPrecompiledContract(&bls12381MapG2{}),
 }
 
 // RunPrecompiledContract runs and evaluates the output of a precompiled contract.
diff --git a/core/vm/contracts_stateful.go b/core/vm/contracts_stateful.go
new file mode 100644
index 0000000..3ef7a9e
--- /dev/null
+++ b/core/vm/contracts_stateful.go
@@ -0,0 +1,165 @@
+package vm
+
+import (
+	"errors"
+	"fmt"
+	"math/big"
+
+	"github.com/ava-labs/coreth/params"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/holiman/uint256"
+)
+
+// PrecompiledContractsApricot contains the default set of pre-compiled Ethereum
+// contracts used in the Istanbul release and the stateful precompiled contracts
+// added for the Avalanche Apricot release.
+// Apricot is incompatible with the YoloV1 Release since it does not include the
+// BLS12-381 Curve Operations added to the set of precompiled contracts
+var PrecompiledContractsApricot = map[common.Address]StatefulPrecompiledContract{
+	common.BytesToAddress([]byte{1}):                                  newWrappedPrecompiledContract(&ecrecover{}),
+	common.BytesToAddress([]byte{2}):                                  newWrappedPrecompiledContract(&sha256hash{}),
+	common.BytesToAddress([]byte{3}):                                  newWrappedPrecompiledContract(&ripemd160hash{}),
+	common.BytesToAddress([]byte{4}):                                  newWrappedPrecompiledContract(&dataCopy{}),
+	common.BytesToAddress([]byte{5}):                                  newWrappedPrecompiledContract(&bigModExp{}),
+	common.BytesToAddress([]byte{6}):                                  newWrappedPrecompiledContract(&bn256AddIstanbul{}),
+	common.BytesToAddress([]byte{7}):                                  newWrappedPrecompiledContract(&bn256ScalarMulIstanbul{}),
+	common.BytesToAddress([]byte{8}):                                  newWrappedPrecompiledContract(&bn256PairingIstanbul{}),
+	common.BytesToAddress([]byte{9}):                                  newWrappedPrecompiledContract(&blake2F{}),
+	common.HexToAddress("0x0100000000000000000000000000000000000000"): &deprecatedContract{msg: "hardcoded genesis contract has been deprecated"},
+	common.HexToAddress("0xffffffffffffffffffffffffffffffffffffff"):   &nativeAssetBalance{gasCost: params.AssetBalanceApricot},
+	common.HexToAddress("0xfffffffffffffffffffffffffffffffffffffe"):   &nativeAssetCall{gasCost: params.AssetCallApricot},
+}
+
+// StatefulPrecompiledContract is the interface for executing a precompiled contract
+// This wraps the PrecompiledContracts native to Ethereum and allows adding in stateful
+// precompiled contracts to support native Avalanche asset transfers.
+type StatefulPrecompiledContract interface {
+	// Run executes a precompiled contract in the current state
+	// assumes that it has already been verified that [caller] can
+	// transfer [value].
+	Run(evm *EVM, caller ContractRef, addr common.Address, value *big.Int, input []byte, suppliedGas uint64, readOnly bool) (ret []byte, remainingGas uint64, err error)
+}
+
+// wrappedPrecompiledContract implements StatefulPrecompiledContract by wrapping stateless native precompiled contracts
+// in Ethereum.
+type wrappedPrecompiledContract struct {
+	p PrecompiledContract
+}
+
+func newWrappedPrecompiledContract(p PrecompiledContract) StatefulPrecompiledContract {
+	return &wrappedPrecompiledContract{p: p}
+}
+
+// Run ...
+func (w *wrappedPrecompiledContract) Run(evm *EVM, caller ContractRef, addr common.Address, value *big.Int, input []byte, suppliedGas uint64, readOnly bool) (ret []byte, remainingGas uint64, err error) {
+	evm.Transfer(evm.StateDB, caller.Address(), addr, value)
+	return RunPrecompiledContract(w.p, input, suppliedGas)
+}
+
+// nativeAssetBalance is a precompiled contract used to retrieve the native asset balance
+type nativeAssetBalance struct {
+	gasCost uint64
+}
+
+// Run implements StatefulPrecompiledContract
+func (b *nativeAssetBalance) Run(evm *EVM, caller ContractRef, addr common.Address, value *big.Int, input []byte, suppliedGas uint64, readOnly bool) (ret []byte, remainingGas uint64, err error) {
+	// input: encodePacked(address 20 bytes, assetID 32 bytes)
+	if value.Sign() != 0 {
+		return nil, suppliedGas, errors.New("cannot transfer value to native asset balance pre-compiled contract")
+	}
+
+	if suppliedGas < b.gasCost {
+		return nil, 0, ErrOutOfGas
+	}
+	remainingGas = suppliedGas - b.gasCost
+
+	if len(input) != 52 {
+		return nil, remainingGas, fmt.Errorf("input to native asset balance must be 52 bytes, containing address [20 bytes] and assetID [32 bytes], but found length: %d", len(input))
+	}
+	address := common.BytesToAddress(input[:20])
+	assetID := new(common.Hash)
+	assetID.SetBytes(input[20:52])
+
+	res, overflow := uint256.FromBig(evm.StateDB.GetBalanceMultiCoin(address, *assetID))
+	log.Info("nativeAssetBalance", "address", address, "assetID", assetID.Hex(), "res", res, "overflow", overflow)
+	if overflow {
+		return nil, remainingGas, errors.New("balance overflow")
+	}
+	return common.LeftPadBytes(res.Bytes(), 32), remainingGas, nil
+}
+
+// nativeAssetCall atomically transfers a native asset to a recipient address as well as calling that
+// address
+type nativeAssetCall struct {
+	gasCost uint64
+}
+
+// Run implements StatefulPrecompiledContract
+func (c *nativeAssetCall) Run(evm *EVM, caller ContractRef, addr common.Address, value *big.Int, input []byte, suppliedGas uint64, readOnly bool) (ret []byte, remainingGas uint64, err error) {
+	// input: encodePacked(address 20 bytes, assetID 32 bytes, assetAmount 32 bytes, callData variable length bytes)
+	if suppliedGas < c.gasCost {
+		return nil, 0, ErrOutOfGas
+	}
+	remainingGas = suppliedGas - c.gasCost
+
+	if readOnly {
+		return nil, remainingGas, errors.New("cannot execute native asset transfer within read only call")
+	}
+
+	if len(input) < 84 {
+		return nil, remainingGas, fmt.Errorf("missing inputs to native asset transfer, expected input of length at least 84, but found %d", len(input))
+	}
+	to := common.BytesToAddress(input[:20])
+	assetID := new(common.Hash)
+	assetID.SetBytes(input[20:52])
+	assetAmount := new(big.Int).SetBytes(input[52:84])
+	callData := input[84:]
+	log.Info("nativeAssetCall", "input", fmt.Sprintf("0x%x", input), "to", to.Hex(), "assetID", assetID.Hex(), "assetAmount", assetAmount, "callData", fmt.Sprintf("0x%x", callData))
+
+	mcerr := evm.Context.CanTransferMC(evm.StateDB, caller.Address(), to, assetID, assetAmount)
+	if mcerr == 1 {
+		log.Info("Insufficient balance for mc transfer")
+		return nil, remainingGas, ErrInsufficientBalance
+	} else if mcerr != 0 {
+		log.Info("incompatible account for mc transfer")
+		return nil, remainingGas, ErrIncompatibleAccount
+	}
+
+	snapshot := evm.StateDB.Snapshot()
+
+	if !evm.StateDB.Exist(to) {
+		log.Info("Creating account entry", "address", to.Hex())
+		remainingGas -= params.CallNewAccountGas
+		evm.StateDB.CreateAccount(to)
+	}
+
+	// Send [value] to [to] address
+	evm.Transfer(evm.StateDB, caller.Address(), to, value)
+	evm.TransferMultiCoin(evm.StateDB, caller.Address(), to, assetID, assetAmount)
+	ret, remainingGas, err = evm.Call(caller, to, callData, remainingGas, big.NewInt(0))
+	log.Info("Finished TransferMultiCoin and call", "return", ret, "remainingGas", remainingGas, "error", err)
+
+	// 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 {
+			remainingGas = 0
+		}
+		// TODO: consider clearing up unused snapshots:
+		//} else {
+		//	evm.StateDB.DiscardSnapshot(snapshot)
+	}
+	return ret, remainingGas, err
+}
+
+type deprecatedContract struct {
+	msg string
+}
+
+// Run ...
+func (d *deprecatedContract) Run(evm *EVM, caller ContractRef, addr common.Address, value *big.Int, input []byte, suppliedGas uint64, readOnly bool) (ret []byte, remainingGas uint64, err error) {
+	return nil, suppliedGas, errors.New(d.msg)
+}
diff --git a/core/vm/evm.go b/core/vm/evm.go
index 54c9c7f..ab04790 100644
--- a/core/vm/evm.go
+++ b/core/vm/evm.go
@@ -34,19 +34,23 @@ var emptyCodeHash = crypto.Keccak256Hash(nil)
 
 type (
 	// CanTransferFunc is the signature of a transfer guard function
-	CanTransferFunc   func(StateDB, common.Address, *big.Int) bool
+	CanTransferFunc func(StateDB, common.Address, *big.Int) bool
+	// CanTransferMCFunc is the signature of a transfer native asset function
 	CanTransferMCFunc func(StateDB, common.Address, common.Address, *common.Hash, *big.Int) int
 	// TransferFunc is the signature of a transfer function
-	TransferFunc   func(StateDB, common.Address, common.Address, *big.Int)
+	TransferFunc func(StateDB, common.Address, common.Address, *big.Int)
+	// TransferMCFunc is the signature of a transfer native asset function
 	TransferMCFunc func(StateDB, common.Address, common.Address, *common.Hash, *big.Int)
 	// GetHashFunc returns the n'th block hash in the blockchain
 	// and is used by the BLOCKHASH EVM op code.
 	GetHashFunc func(uint64) common.Hash
 )
 
-func (evm *EVM) precompile(addr common.Address) (PrecompiledContract, bool) {
-	var precompiles map[common.Address]PrecompiledContract
+func (evm *EVM) precompile(addr common.Address) (StatefulPrecompiledContract, bool) {
+	var precompiles map[common.Address]StatefulPrecompiledContract
 	switch {
+	case evm.chainRules.IsApricot:
+		precompiles = PrecompiledContractsApricot
 	case evm.chainRules.IsYoloV1:
 		precompiles = PrecompiledContractsYoloV1
 	case evm.chainRules.IsIstanbul:
@@ -222,7 +226,6 @@ func (evm *EVM) Call(caller ContractRef, addr common.Address, input []byte, gas
 		}
 		evm.StateDB.CreateAccount(addr)
 	}
-	evm.Transfer(evm.StateDB, caller.Address(), addr, value)
 
 	// Capture the tracer start/end events in debug mode
 	if evm.vmConfig.Debug && evm.depth == 0 {
@@ -233,8 +236,9 @@ func (evm *EVM) Call(caller ContractRef, addr common.Address, input []byte, gas
 	}
 
 	if isPrecompile {
-		ret, gas, err = RunPrecompiledContract(p, input, gas)
+		ret, gas, err = p.Run(evm, caller, addr, value, input, gas, false)
 	} else {
+		evm.Transfer(evm.StateDB, caller.Address(), addr, 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.
 		code := evm.StateDB.GetCode(addr)
@@ -371,7 +375,7 @@ func (evm *EVM) CallCode(caller ContractRef, addr common.Address, input []byte,
 
 	// It is allowed to call precompiles, even via delegatecall
 	if p, isPrecompile := evm.precompile(addr); isPrecompile {
-		ret, gas, err = RunPrecompiledContract(p, input, gas)
+		ret, gas, err = p.Run(evm, caller, addr, value, input, gas, false)
 	} else {
 		addrCopy := addr
 		// Initialise a new contract and set the code that is to be used by the EVM.
@@ -407,7 +411,7 @@ func (evm *EVM) DelegateCall(caller ContractRef, addr common.Address, input []by
 
 	// It is allowed to call precompiles, even via delegatecall
 	if p, isPrecompile := evm.precompile(addr); isPrecompile {
-		ret, gas, err = RunPrecompiledContract(p, input, gas)
+		ret, gas, err = p.Run(evm, caller, addr, big0, input, gas, false)
 	} else {
 		addrCopy := addr
 		// Initialise a new contract and make initialise the delegate values
@@ -451,7 +455,7 @@ func (evm *EVM) StaticCall(caller ContractRef, addr common.Address, input []byte
 	evm.StateDB.AddBalance(addr, big0)
 
 	if p, isPrecompile := evm.precompile(addr); isPrecompile {
-		ret, gas, err = RunPrecompiledContract(p, input, gas)
+		ret, gas, err = p.Run(evm, caller, addr, big0, input, gas, true)
 	} 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'
diff --git a/core/vm/interpreter.go b/core/vm/interpreter.go
index a114a8d..1292650 100644
--- a/core/vm/interpreter.go
+++ b/core/vm/interpreter.go
@@ -26,6 +26,7 @@ import (
 )
 
 var (
+	// BuiltinAddr ...
 	BuiltinAddr = common.Address{
 		1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 		0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
@@ -106,6 +107,8 @@ func NewEVMInterpreter(evm *EVM, cfg Config) *EVMInterpreter {
 	if cfg.JumpTable[STOP] == nil {
 		var jt JumpTable
 		switch {
+		case evm.chainRules.IsApricot:
+			jt = apricotInstructionSet
 		case evm.chainRules.IsYoloV1:
 			jt = yoloV1InstructionSet
 		case evm.chainRules.IsIstanbul:
@@ -146,6 +149,15 @@ func NewEVMInterpreter(evm *EVM, cfg Config) *EVMInterpreter {
 // considered a revert-and-consume-all-gas operation except for
 // ErrExecutionReverted which means revert-and-keep-gas-left.
 func (in *EVMInterpreter) Run(contract *Contract, input []byte, readOnly bool) (ret []byte, err error) {
+	// TODO remove after Apricot network upgrade.
+	// [BuiltinAddr] is overridden by a precompile in Apricot.
+	// This makes any call to [BuiltinAddr] a no-op once the network
+	// upgrade occurs. Then in the upgrade after the hard fork, this
+	// code can be safely removed.
+	// This can't occur before the hard fork because it would change
+	// the behavior of upgraded nodes before the hard fork occurs
+	// since there is no mechanism to change this code based on the
+	// block height.
 	if contract.Address() == BuiltinAddr {
 		self := AccountRef(contract.Caller())
 		if _, ok := contract.caller.(*Contract); ok {
diff --git a/core/vm/jump_table.go b/core/vm/jump_table.go
index 9b538d4..fc12f93 100644
--- a/core/vm/jump_table.go
+++ b/core/vm/jump_table.go
@@ -49,6 +49,7 @@ type operation struct {
 }
 
 var (
+	apricotInstructionSet          = newApricotInstructionSet()
 	frontierInstructionSet         = newFrontierInstructionSet()
 	homesteadInstructionSet        = newHomesteadInstructionSet()
 	tangerineWhistleInstructionSet = newTangerineWhistleInstructionSet()
@@ -1043,3 +1044,13 @@ func newFrontierInstructionSet() JumpTable {
 		},
 	}
 }
+
+// newApricotInstructionSet returns a new instruction set
+// compatible with the Apricot release, which deprecates
+// added instructions: CALLEX and BALANCEMC
+func newApricotInstructionSet() JumpTable {
+	instructionSet := newFrontierInstructionSet()
+	instructionSet[CALLEX] = nil
+	instructionSet[BALANCEMC] = nil
+	return instructionSet
+}
diff --git a/core/vm/opcodes.go b/core/vm/opcodes.go
index c5097f8..cc9518e 100644
--- a/core/vm/opcodes.go
+++ b/core/vm/opcodes.go
@@ -208,6 +208,7 @@ const (
 	SWAP
 )
 
+// Constants supporting native asset operations
 const (
 	BALANCEMC = 0xcd
 	//EMC       = 0xce