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nes: mmc5: fix uncharted waters, and presumably some other 16K WRAM games

This commit is contained in:
goyuken 2014-02-24 01:01:15 +00:00
parent cdd19396d4
commit b1dc3f0f48
1 changed files with 68 additions and 25 deletions
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93
BizHawk.Emulation.Cores/Consoles/Nintendo/NES/Boards/ExROM.cs
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@ -23,7 +23,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
{
//configuraton
int prg_bank_mask_8k, chr_bank_mask_1k; //board setup (to be isolated from mmc5 code later, when we need the separate mmc5 class)
int wram_bank_mask_8k;
//state
int irq_target, irq_counter;
@ -100,6 +99,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
switch (Cart.board_type)
{
case "MAPPER005":
Cart.wram_size = 64;
break;
case "NES-ELROM": //Castlevania 3 - Dracula's Curse (U)
case "HVC-ELROM":
@ -126,7 +126,6 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
chr_bank_mask_1k = Cart.chr_size - 1;
else
chr_bank_mask_1k = Cart.vram_size - 1;
wram_bank_mask_8k = Cart.wram_size / 8 - 1;
PoweronState();
@ -150,24 +149,67 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
SetMirrorType(EMirrorType.Vertical);
}
int MapWRAM(int addr)
{
int bank_8k = wram_bank & wram_bank_mask_8k;
int ofs = addr & ((1 << 13) - 1);
addr = (bank_8k << 13) | ofs;
return addr;
}
int MapPRG(int addr, out bool ram)
int PRGGetBank(int addr, out bool ram)
{
int bank_8k = addr >> 13;
int ofs = addr & ((1 << 13) - 1);
bank_8k = prg_banks_8k[bank_8k];
ram = (bank_8k & 0x80) == 0;
bank_8k &= ~0x80;
if (!ram)
bank_8k &= prg_bank_mask_8k;
return (bank_8k << 13) | ofs;
return bank_8k;
}
// wram:
// [.... .CBB]
// C = chip select
// B = bank select (8K banks)
// the following configurations are known:
// 1) no wram
// 2) 8K wram: 1x 8K
// 3) 16K wram: 2x 8K
// 4) 32K wram: 1x 32K
//
// for iNES, we assume 64K wram
int? MaskWRAM(int bank)
{
bank &= 7;
switch (Cart.wram_size)
{
case 0:
return null;
case 8:
if (bank >= 4)
return null;
else
return 0;
case 16:
return bank >> 2;
case 32:
if (bank >= 4)
return null;
else
return bank & 3;
case 64:
return bank;
default:
throw new Exception();
}
}
void WriteWRAMActual(int bank, int offs, byte value)
{
int? bbank = MaskWRAM(bank);
if (bbank.HasValue)
WRAM[(int)bbank << 13 | offs] = value;
}
byte ReadWRAMActual(int bank, int offs)
{
int? bbank = MaskWRAM(bank);
if (bbank.HasValue)
return WRAM[(int)bbank << 13 | offs];
else
return NES.DB;
}
//this could be handy, but probably not. I did it on accident.
@ -304,10 +346,10 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
switch (nt)
{
case 0: //NES internal NTA
base.WritePPU(0x2000 + offset, value);
NES.CIRAM[offset] = value;
break;
case 1: //NES internal NTB
base.WritePPU(0x2400 + offset, value);
NES.CIRAM[0x400 | offset] = value;
break;
case 2: //use ExRAM as NT
//TODO - additional r/w security
@ -323,25 +365,25 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
public override void WriteWRAM(int addr, byte value)
{
addr = MapWRAM(addr);
WRAM[addr] = value;
WriteWRAMActual(wram_bank, addr & 0x1fff, value);
}
public override byte ReadWRAM(int addr)
{
addr = MapWRAM(addr);
return WRAM[addr];
return ReadWRAMActual(wram_bank, addr & 0x1fff);
}
public override byte ReadPRG(int addr)
{
bool ram;
byte ret;
int mapaddr = MapPRG(addr, out ram);
int offs = addr & 0x1fff;
int bank = PRGGetBank(addr, out ram);
if (ram)
ret = WRAM[mapaddr];
ret = ReadWRAMActual(bank, offs);
else
ret = ROM[mapaddr];
ret = ROM[bank << 13 | offs];
if (addr < 0x4000)
audio.ReadROMTrigger(ret);
return ret;
@ -350,8 +392,9 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
public override void WritePRG(int addr, byte value)
{
bool ram;
addr = MapPRG(addr, out ram);
if (ram) WRAM[addr] = value;
int bank = PRGGetBank(addr, out ram);
if (ram)
WriteWRAMActual(bank, addr & 0x1fff, value);
}
public override void WriteEXP(int addr, byte value)