BizHawk/BizHawk.Emulation/Consoles/Nintendo/NES/Boards/JALECO_SS8806.cs

287 lines
6.7 KiB
C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace BizHawk.Emulation.Consoles.Nintendo
{
class JALECO_SS8806 : NES.NESBoardBase
{
//http://wiki.nesdev.com/w/index.php/INES_Mapper_018
ByteBuffer prg_banks_8k = new ByteBuffer(4);
ByteBuffer chr_banks_1k = new ByteBuffer(8);
int chr_bank_mask_1k, prg_bank_mask_8k;
int ppuclock;
int irqclock;
int irqreload;
int irqcountwidth;
bool irqcountpaused;
public override bool Configure(NES.EDetectionOrigin origin)
{
//analyze board type
switch (Cart.board_type)
{
case "MAPPER018":
case "JALECO-JF-24": //TODO: there will be many boards to list here
break;
default:
return false;
}
chr_bank_mask_1k = Cart.chr_size / 1 - 1;
prg_bank_mask_8k = Cart.prg_size / 8 - 1;
prg_banks_8k[3] = 0xFF;
// i have no idea what power-on defaults are supposed to be used
ppuclock = 0;
irqclock = 0xffff;
irqreload = 0xffff;
irqcountwidth = 16;
irqcountpaused = true;
SetMirrorType(EMirrorType.Horizontal);
return true;
}
public override void SyncState(Serializer ser)
{
ser.Sync("prg_banks_8k", ref prg_banks_8k);
ser.Sync("chr_banks_1k", ref chr_banks_1k);
ser.Sync("ppuclock", ref ppuclock);
ser.Sync("irqclock", ref irqclock);
ser.Sync("irqreload", ref irqreload);
ser.Sync("irqcountwidth", ref irqcountwidth);
ser.Sync("irqcountpaused", ref irqcountpaused);
base.SyncState(ser);
}
public override void Dispose()
{
prg_banks_8k.Dispose();
chr_banks_1k.Dispose();
base.Dispose();
}
public override void WritePRG(int addr, byte value)
{
addr += 0x8000; //temporary
addr &= 0xF003;
switch (addr)
{
case 0x8000:
prg_banks_8k[0] &= 0xf0;
prg_banks_8k[0] |= (byte)(value & 0x0F);
break;
case 0x8001:
prg_banks_8k[0] &= 0x0f;
prg_banks_8k[0] |= (byte)((value & 0x0F) << 4);
break;
case 0x8002:
prg_banks_8k[1] &= 0xf0;
prg_banks_8k[1] |= (byte)(value & 0x0F);
break;
case 0x8003:
prg_banks_8k[1] &= 0x0f;
prg_banks_8k[1] |= (byte)((value & 0x0F) << 4);
break;
case 0x9000:
prg_banks_8k[2] &= 0xf0;
prg_banks_8k[2] |= (byte)(value & 0x0F);
break;
case 0x9001:
prg_banks_8k[2] &= 0x0f;
prg_banks_8k[2] |= (byte)((value & 0x0F) << 4);
break;
case 0xA000:
chr_banks_1k[0] &= 0xf0;
chr_banks_1k[0] |= (byte)(value & 0x0F);
break;
case 0xA001:
chr_banks_1k[0] &= 0x0f;
chr_banks_1k[0] |= (byte)((value & 0x0F) << 4);
break;
case 0xA002:
chr_banks_1k[1] &= 0xf0;
chr_banks_1k[1] |= (byte)(value & 0x0F);
break;
case 0xA003:
chr_banks_1k[1] &= 0x0f;
chr_banks_1k[1] |= (byte)((value & 0x0F) << 4);
break;
case 0xB000:
chr_banks_1k[2] &= 0xf0;
chr_banks_1k[2] |= (byte)(value & 0x0F);
break;
case 0xB001:
chr_banks_1k[2] &= 0x0f;
chr_banks_1k[2] |= (byte)((value & 0x0F) << 4);
break;
case 0xB002:
chr_banks_1k[3] &= 0xf0;
chr_banks_1k[3] |= (byte)(value & 0x0F);
break;
case 0xB003:
chr_banks_1k[3] &= 0x0f;
chr_banks_1k[3] |= (byte)((value & 0x0F) << 4);
break;
case 0xC000:
chr_banks_1k[4] &= 0xf0;
chr_banks_1k[4] |= (byte)(value & 0x0F);
break;
case 0xC001:
chr_banks_1k[4] &= 0x0f;
chr_banks_1k[4] |= (byte)((value & 0x0F) << 4);
break;
case 0xC002:
chr_banks_1k[5] &= 0xf0;
chr_banks_1k[5] |= (byte)(value & 0x0F);
break;
case 0xC003:
chr_banks_1k[5] &= 0x0f;
chr_banks_1k[5] |= (byte)((value & 0x0F) << 4);
break;
case 0xD000:
chr_banks_1k[6] &= 0xf0;
chr_banks_1k[6] |= (byte)(value & 0x0F);
break;
case 0xD001:
chr_banks_1k[6] &= 0x0f;
chr_banks_1k[6] |= (byte)((value & 0x0F) << 4);
break;
case 0xD002:
chr_banks_1k[7] &= 0xf0;
chr_banks_1k[7] |= (byte)(value & 0x0F);
break;
case 0xD003:
chr_banks_1k[7] &= 0x0f;
chr_banks_1k[7] |= (byte)((value & 0x0F) << 4);
break;
case 0xE000:
irqreload &= 0xfff0;
irqreload |= value & 0xf;
break;
case 0xE001:
irqreload &= 0xff0f;
irqreload |= (value & 0xf) << 4;
break;
case 0xE002:
irqreload &= 0xf0ff;
irqreload |= (value & 0xf) << 8;
break;
case 0xE003:
irqreload &= 0x0fff;
irqreload |= (value & 0xf) << 12;
break;
case 0xF002:
switch (value & 0x03)
{
case 0:
SetMirrorType(EMirrorType.Horizontal);
break;
case 1:
SetMirrorType(EMirrorType.Vertical);
break;
case 2:
SetMirrorType(EMirrorType.OneScreenA);
break;
case 3:
SetMirrorType(EMirrorType.OneScreenB);
break;
}
break;
case 0xF000:
// ack irq and reset
IRQSignal = false;
irqclock = irqreload;
break;
case 0xF001:
// ack irq and set values
IRQSignal = false;
irqcountpaused = (value & 1) == 0;
if ((value & 8) == 8)
irqcountwidth = 4;
else if ((value & 4) == 4)
irqcountwidth = 8;
else if ((value & 2) == 2)
irqcountwidth = 12;
else
irqcountwidth = 16;
break;
case 0xF003:
// sound chip µPD7756C
break;
}
}
public override void ClockCPU()
{
//ppuclock++;
//if (ppuclock == 3)
//{
//ppuclock = 0;
if (!irqcountpaused)
{
int newclock = irqclock - 1;
if (squeeze(newclock) > squeeze(irqclock))
{
IRQSignal = true;
irqclock = irqreload;
}
else
irqclock = newclock;
}
//}
}
/// <summary>
/// emulate underflow for the appropriate number of bits
/// </summary>
uint squeeze(int input)
{
unchecked
{
uint uinput = (uint)input;
uinput <<= (32 - irqcountwidth);
uinput >>= (32 - irqcountwidth);
return uinput;
}
}
public override byte ReadPRG(int addr)
{
int bank_8k = addr >> 13;
bank_8k = prg_banks_8k[bank_8k];
bank_8k &= prg_bank_mask_8k;
return ROM[(bank_8k * 0x2000) + (addr & 0x1FFF)];
}
private int MapCHR(int addr)
{
int bank_1k = addr >> 10;
bank_1k = chr_banks_1k[bank_1k];
bank_1k &= chr_bank_mask_1k;
addr = (bank_1k << 10) | (addr & 0x3FF);
return addr;
}
public override byte ReadPPU(int addr)
{
if (addr < 0x2000)
{
addr = MapCHR(addr);
if (VROM != null)
return VROM[addr];
else return VRAM[addr];
}
else return base.ReadPPU(addr);
}
}
}