AxibugEmuOnline/Core/VirtualNes.Core/Mapper/Mapper142.cs

116 lines
3.3 KiB
C#
Raw Normal View History

//////////////////////////////////////////////////////////////////////////
// Mapper142 SMB2J //
//////////////////////////////////////////////////////////////////////////
using System;
using static VirtualNes.Core.CPU;
using static VirtualNes.MMU;
using BYTE = System.Byte;
using INT = System.Int32;
namespace VirtualNes.Core
{
public class Mapper142 : Mapper
{
BYTE prg_sel;
BYTE irq_enable;
INT irq_counter;
public Mapper142(NES parent) : base(parent)
{
}
public override void Reset()
{
prg_sel = 0;
irq_enable = 0;
irq_counter = 0;
SetPROM_8K_Bank(3, 0);
SetPROM_8K_Bank(7, 0x0F);
if (VROM_1K_SIZE != 0)
{
SetVROM_8K_Bank(0);
}
}
//void Mapper142::Write(WORD addr, BYTE data)
public override void Write(ushort addr, byte data)
{
switch (addr & 0xF000)
{
case 0x8000:
irq_counter = (irq_counter & 0xFFF0) | ((data & 0x0F) << 0);
break;
case 0x9000:
irq_counter = (irq_counter & 0xFF0F) | ((data & 0x0F) << 4);
break;
case 0xA000:
irq_counter = (irq_counter & 0xF0FF) | ((data & 0x0F) << 8);
break;
case 0xB000:
irq_counter = (irq_counter & 0x0FFF) | ((data & 0x0F) << 12);
break;
case 0xC000:
irq_enable = (byte)(data & 0x0F);
nes.cpu.ClrIRQ(IRQ_MAPPER);
break;
case 0xE000:
prg_sel = (byte)(data & 0x0F);
break;
case 0xF000:
switch (prg_sel)
{
case 1: SetPROM_8K_Bank(4, data & 0x0F); break;
case 2: SetPROM_8K_Bank(5, data & 0x0F); break;
case 3: SetPROM_8K_Bank(6, data & 0x0F); break;
case 4: SetPROM_8K_Bank(3, data & 0x0F); break;
}
break;
}
}
//void Mapper142::HSync(INT scanline)
public override void HSync(int scanline)
{
if (irq_enable != 0)
{
if (irq_counter > (0xFFFF - 113))
{
irq_counter = 0;
nes.cpu.SetIRQ(IRQ_MAPPER);
}
else
{
irq_counter += 113;
}
}
}
//void Mapper142::SaveState(LPBYTE p)
public override void SaveState(byte[] p)
{
p[0] = prg_sel;
p[0] = irq_enable;
//*(INT*)&p[2] = irq_counter;
BitConverter.GetBytes(irq_counter).CopyTo(p, 2);
}
//void Mapper142::LoadState(LPBYTE p)
public override void LoadState(byte[] p)
{
prg_sel = p[0];
irq_enable = p[1];
//irq_counter = *(INT*)&p[2];
irq_counter = BitConverter.ToInt32(p, 2);
}
public override bool IsStateSave()
{
return true;
}
}
}