From 4857ed73e80619d6046af223a61242e99e81235a Mon Sep 17 00:00:00 2001
From: Determinant <ted.sybil@gmail.com>
Date: Tue, 14 Nov 2017 20:38:45 -0500
Subject: ppu optimization

---
 src/mapper.rs | 71 +++++++++++++++++++++++++++++++----------------------------
 1 file changed, 37 insertions(+), 34 deletions(-)

(limited to 'src/mapper.rs')

diff --git a/src/mapper.rs b/src/mapper.rs
index c54acb4..210b59f 100644
--- a/src/mapper.rs
+++ b/src/mapper.rs
@@ -1,61 +1,64 @@
 #![allow(dead_code)]
 use memory::VMem;
 use cartridge::{Cartridge, BankType};
-use core::cell::RefCell;
+use core::cell::UnsafeCell;
 
 pub struct Mapper2<'a> {
     cart: &'a Cartridge,
-    prg_bank1: RefCell<&'a [u8]>,
-    prg_bank2: RefCell<&'a [u8]>,
-    chr_bank: RefCell<&'a mut [u8]>,
-    sram: RefCell<&'a mut [u8]>,
+    prg_bank1: UnsafeCell<&'a [u8]>,
+    prg_bank2: UnsafeCell<&'a [u8]>,
+    chr_bank: UnsafeCell<&'a mut [u8]>,
+    sram: UnsafeCell<&'a mut [u8]>,
     prg_nbank: usize
 }
 
 impl<'a> VMem for Mapper2<'a> {
     fn read(&self, addr: u16) -> u8 {
         let addr = addr as usize;
-        if addr < 0x2000 {         /* 0x2000 size bank */
-            self.chr_bank.borrow()[addr]
-        } else if addr >= 0xc000 { /* 0x4000 size bank */
-            self.prg_bank2.borrow()[addr - 0xc000]
-        } else if addr >= 0x8000 { /* 0x4000 size bank */
-            self.prg_bank1.borrow()[addr - 0x8000]
-        } else if addr >= 0x6000 {
-            self.sram.borrow()[addr - 0x6000]
-        } else {
-            panic!("unmapped address: 0x{:04x}", addr)
+        unsafe {
+            if addr < 0x2000 {         /* 0x2000 size bank */
+                (*self.chr_bank.get())[addr]
+            } else if addr >= 0xc000 { /* 0x4000 size bank */
+                (*self.prg_bank2.get())[addr - 0xc000]
+            } else if addr >= 0x8000 { /* 0x4000 size bank */
+                (*self.prg_bank1.get())[addr - 0x8000]
+            } else if addr >= 0x6000 {
+                (*self.sram.get())[addr - 0x6000]
+            } else {
+                panic!("unmapped address: 0x{:04x}", addr)
+            }
         }
     }
 
     fn write(&self, addr: u16, data: u8) {
         let addr = addr as usize;
-        if addr < 0x2000 {
-            self.chr_bank.borrow_mut()[addr] = data;
-        } else if addr >= 0x8000 {
-            (*self.prg_bank1.borrow_mut()) = unsafe {
-                &*self.cart.get_bank(((data as usize) % self.prg_nbank) << 14,
-                                    0x4000,
-                                    BankType::PrgRom)};
-        } else if addr >= 0x6000 {
-            self.sram.borrow_mut()[addr - 0x6000] = data;
-        } else {
-            panic!("invalid write to address: 0x{:04x}", addr);
+        unsafe {
+            if addr < 0x2000 {
+                (*self.chr_bank.get())[addr] = data;
+            } else if addr >= 0x8000 {
+                (*self.prg_bank1.get()) =
+                    &*self.cart.get_bank(((data as usize) % self.prg_nbank) << 14,
+                    0x4000,
+                    BankType::PrgRom);
+            } else if addr >= 0x6000 {
+                (*self.sram.get())[addr - 0x6000] = data;
+            } else {
+                panic!("invalid write to address: 0x{:04x}", addr);
+            }
         }
     }
 }
 
 impl<'a> Mapper2<'a> {
-    pub fn new(cart: *const Cartridge) -> Self {
+    pub fn new(cart: &'a Cartridge) -> Self {
         unsafe {
-            let cart = &*cart;
             let nbank = cart.get_size(BankType::PrgRom) >> 14;
-            Mapper2{cart: &cart,
-            prg_bank1: RefCell::new(&*cart.get_bank(0, 0x4000, BankType::PrgRom)),
-            prg_bank2: RefCell::new(&*cart.get_bank((nbank - 1) << 14, 0x4000, BankType::PrgRom)),
-            chr_bank: RefCell::new(&mut *cart.get_bank(0, 0x2000, BankType::ChrRom)),
-            sram: RefCell::new(&mut *cart.get_bank(0, 0x2000, BankType::Sram)),
-            prg_nbank: nbank}
+            Mapper2{cart,
+                prg_bank1: UnsafeCell::new(&*cart.get_bank(0, 0x4000, BankType::PrgRom)),
+                prg_bank2: UnsafeCell::new(&*cart.get_bank((nbank - 1) << 14, 0x4000, BankType::PrgRom)),
+                chr_bank: UnsafeCell::new(&mut *cart.get_bank(0, 0x2000, BankType::ChrRom)),
+                sram: UnsafeCell::new(&mut *cart.get_bank(0, 0x2000, BankType::Sram)),
+                prg_nbank: nbank}
         }
     }
 }
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