mapper254.cpp

著名的任天堂FC游戏机模拟器VirtuaNes 085版的源码!

//////////////////////////////////////////////////////////////////////////
// Mapper254  Pokemon Pirate Cart                                       //
//////////////////////////////////////////////////////////////////////////
void	Mapper254::Reset()
{
	for( INT i = 0; i < 8; i++ ) {
		reg[i] = 0x00;
	}

	protectflag = 0;

	prg0 = 0;
	prg1 = 1;
	SetBank_CPU();

	chr01 = 0;
	chr23 = 2;
	chr4  = 4;
	chr5  = 5;
	chr6  = 6;
	chr7  = 7;
	SetBank_PPU();

	irq_enable = 0;	// Disable
	irq_counter = 0;
	irq_latch = 0;
	irq_request = 0;
}

void	Mapper254::WriteLow( WORD addr, BYTE data )
{
	switch( addr & 0xF000 ) {
		case	0x6000:
		case	0x7000:
			CPU_MEM_BANK[addr>>13][addr&0x1FFF] = data;
			break;
	}

}
BYTE	Mapper254::ReadLow( WORD addr )
{
	if( addr>=0x6000 ) {
		if( protectflag ) {
			return	(CPU_MEM_BANK[addr>>13][addr&0x1FFF]);
		} else {
			return	((CPU_MEM_BANK[addr>>13][addr&0x1FFF])^0x1);
		}
	}
	return	Mapper::ReadLow( addr );
}

void	Mapper254::Write( WORD addr, BYTE data )
{
	switch( addr & 0xE001 ) {
		case	0x8000:
			protectflag=0xFF;
			reg[0] = data;
			SetBank_CPU();
			SetBank_PPU();
			break;
		case	0x8001:
			reg[1] = data;

			switch( reg[0] & 0x07 ) {
				case	0x00:
					chr01 = data & 0xFE;
					SetBank_PPU();
					break;
				case	0x01:
					chr23 = data & 0xFE;
					SetBank_PPU();
					break;
				case	0x02:
					chr4 = data;
					SetBank_PPU();
					break;
				case	0x03:
					chr5 = data;
					SetBank_PPU();
					break;
				case	0x04:
					chr6 = data;
					SetBank_PPU();
					break;
				case	0x05:
					chr7 = data;
					SetBank_PPU();
					break;
				case	0x06:
					prg0 = data;
					SetBank_CPU();
					break;
				case	0x07:
					prg1 = data;
					SetBank_CPU();
					break;
			}
			break;
		case	0xA000:
			reg[2] = data;
			if( !nes->rom->Is4SCREEN() ) {
				if( data & 0x01 ) SetVRAM_Mirror( VRAM_HMIRROR );
				else		  SetVRAM_Mirror( VRAM_VMIRROR );
			}
			break;
		case	0xA001:
			reg[3] = data;
			break;
		case	0xC000:
			reg[4] = data;
			irq_counter = data;
			irq_request = 0;
			nes->cpu->ClrIRQ( IRQ_MAPPER );
			break;
		case	0xC001:
			reg[5] = data;
			irq_latch = data;
			irq_request = 0;
			nes->cpu->ClrIRQ( IRQ_MAPPER );
			break;
		case	0xE000:
			reg[6] = data;
			irq_enable = 0;
			irq_request = 0;
			nes->cpu->ClrIRQ( IRQ_MAPPER );
			break;
		case	0xE001:
			reg[7] = data;
			irq_enable = 1;
			irq_request = 0;
			nes->cpu->ClrIRQ( IRQ_MAPPER );
			break;
	}
}

void	Mapper254::Clock( INT cycles )
{
//	if( irq_request && (nes->GetIrqType() == NES::IRQ_CLOCK) ) {
//		nes->cpu->IRQ_NotPending();
//	}
}

void	Mapper254::HSync( INT scanline )
{
	if( (scanline >= 0 && scanline <= 239) ) {
		if( nes->ppu->IsDispON() ) {
			if( irq_enable && !irq_request ) {
				if( scanline == 0 ) {
					if( irq_counter ) {
						irq_counter--;
					}
				}
				if( !(irq_counter--) ) {
					irq_request = 0xFF;
					irq_counter = irq_latch;
					nes->cpu->SetIRQ( IRQ_MAPPER );
				}
			}
		}
	}
//	if( irq_request && (nes->GetIrqType() == NES::IRQ_HSYNC) ) {
//		nes->cpu->IRQ_NotPending();
//	}
}

void	Mapper254::SetBank_CPU()
{
	if( reg[0] & 0x40 ) {
		SetPROM_32K_Bank( PROM_8K_SIZE-2, prg1, prg0, PROM_8K_SIZE-1 );
	} else {
		SetPROM_32K_Bank( prg0, prg1, PROM_8K_SIZE-2, PROM_8K_SIZE-1 );
	}
}

void	Mapper254::SetBank_PPU()
{

	if( VROM_1K_SIZE ) {
		if( reg[0] & 0x80 ) {
			SetVROM_8K_Bank( chr4, chr5, chr6, chr7,
					 chr01, chr01+1, chr23, chr23+1 );
		} else {
			SetVROM_8K_Bank( chr01, chr01+1, chr23, chr23+1,
					 chr4, chr5, chr6, chr7 );
		}
	} else {
		if( reg[0] & 0x80 ) {
			SetCRAM_1K_Bank( 4, (chr01+0)&0x07 );
			SetCRAM_1K_Bank( 5, (chr01+1)&0x07 );
			SetCRAM_1K_Bank( 6, (chr23+0)&0x07 );
			SetCRAM_1K_Bank( 7, (chr23+1)&0x07 );
			SetCRAM_1K_Bank( 0, chr4&0x07 );
			SetCRAM_1K_Bank( 1, chr5&0x07 );
			SetCRAM_1K_Bank( 2, chr6&0x07 );
			SetCRAM_1K_Bank( 3, chr7&0x07 );
		} else {
			SetCRAM_1K_Bank( 0, (chr01+0)&0x07 );
			SetCRAM_1K_Bank( 1, (chr01+1)&0x07 );
			SetCRAM_1K_Bank( 2, (chr23+0)&0x07 );
			SetCRAM_1K_Bank( 3, (chr23+1)&0x07 );
			SetCRAM_1K_Bank( 4, chr4&0x07 );
			SetCRAM_1K_Bank( 5, chr5&0x07 );
			SetCRAM_1K_Bank( 6, chr6&0x07 );
			SetCRAM_1K_Bank( 7, chr7&0x07 );
		}
	}
}

void	Mapper254::SaveState( LPBYTE p )
{
	for( INT i = 0; i < 8; i++ ) {
		p[i] = reg[i];
	}
	p[ 8] = prg0;
	p[ 9] = prg1;
	p[10] = chr01;
	p[11] = chr23;
	p[12] = chr4;
	p[13] = chr5;
	p[14] = chr6;
	p[15] = chr7;
	p[16] = irq_enable;
	p[17] = irq_counter;
	p[18] = irq_latch;
	p[19] = irq_request;
	p[20] = protectflag;
}

void	Mapper254::LoadState( LPBYTE p )
{
	for( INT i = 0; i < 8; i++ ) {
		reg[i] = p[i];
	}
	prg0  = p[ 8];
	prg1  = p[ 9];
	chr01 = p[10];
	chr23 = p[11];
	chr4  = p[12];
	chr5  = p[13];
	chr6  = p[14];
	chr7  = p[15];
	irq_enable  = p[16];
	irq_counter = p[17];
	irq_latch   = p[18];
	irq_request = p[19];
	protectflag = p[20];
}