AxibugEmuOnline/References/VirtuaNESex_src_191105/NES/Mapper/Mapper100.cpp

//////////////////////////////////////////////////////////////////////////
// Mapper100  Nesticle MMC3                                             //
//////////////////////////////////////////////////////////////////////////
void	Mapper100::Reset()
{
	for( INT i = 0; i < 8; i++ ) {
		reg[i] = 0x00;
	}

	prg0 = 0;
	prg1 = 1;
	prg2 = PROM_8K_SIZE-2;
	prg3 = PROM_8K_SIZE-1;
	SetBank_CPU();

	if( VROM_1K_SIZE ) {
		chr0 = 0;
		chr1 = 1;
		chr2 = 2;
		chr3 = 3;
		chr4 = 4;
		chr5 = 5;
		chr6 = 6;
		chr7 = 7;
		SetBank_PPU();
	} else {
		chr0 = chr2 = chr4 = chr5 = chr6 = chr7 = 0;
		chr1 = chr3 = 1;
	}

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

void	Mapper100::Write( WORD addr, BYTE data )
{
	switch( addr & 0xE001 ) {
		case	0x8000:
			reg[0] = data;
			break;
		case	0x8001:
			reg[1] = data;

			switch( reg[0] & 0xC7 ) {
				case	0x00:
					if( VROM_1K_SIZE ) {
						chr0 = data&0xFE;
						chr1 = chr0+1;
						SetBank_PPU();
					}
					break;
				case	0x01:
					if( VROM_1K_SIZE ) {
						chr2 = data&0xFE;
						chr3 = chr2+1;
						SetBank_PPU();
					}
					break;
				case	0x02:
					if( VROM_1K_SIZE ) {
						chr4 = data;
						SetBank_PPU();
					}
					break;
				case	0x03:
					if( VROM_1K_SIZE ) {
						chr5 = data;
						SetBank_PPU();
					}
					break;
				case	0x04:
					if( VROM_1K_SIZE ) {
						chr6 = data;
						SetBank_PPU();
					}
					break;
				case	0x05:
					if( VROM_1K_SIZE ) {
						chr7 = data;
						SetBank_PPU();
					}
					break;

				case	0x06:
					prg0 = data;
					SetBank_CPU();
					break;
				case	0x07:
					prg1 = data;
					SetBank_CPU();
					break;
				case	0x46:
					prg2 = data;
					SetBank_CPU();
					break;
				case	0x47:
					prg3 = data;
					SetBank_CPU();
					break;

				case	0x80:
					if( VROM_1K_SIZE ) {
						chr4 = data&0xFE;
						chr5 = chr4+1;
						SetBank_PPU();
					}
					break;
				case	0x81:
					if( VROM_1K_SIZE ) {
						chr6 = data&0xFE;
						chr7 = chr6+1;
						SetBank_PPU();
					}
					break;
				case	0x82:
					if( VROM_1K_SIZE ) {
						chr0 = data;
						SetBank_PPU();
					}
					break;
				case	0x83:
					if( VROM_1K_SIZE ) {
						chr1 = data;
						SetBank_PPU();
					}
					break;
				case	0x84:
					if( VROM_1K_SIZE ) {
						chr2 = data;
						SetBank_PPU();
					}
					break;
				case	0x85:
					if( VROM_1K_SIZE ) {
						chr3 = data;
						SetBank_PPU();
					}
					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;
			break;
		case	0xC001:
			reg[5] = data;
			irq_latch = data;
			break;
		case	0xE000:
			reg[6] = data;
			irq_enable = 0;
			nes->cpu->ClrIRQ( IRQ_MAPPER );
			break;
		case	0xE001:
			reg[7] = data;
			irq_enable = 0xFF;
			break;
	}
}

void	Mapper100::HSync( INT scanline )
{
	if( (scanline >= 0 && scanline <= 239) ) {
		if( nes->ppu->IsDispON() ) {
			if( irq_enable ) {
				if( !(irq_counter--) ) {
					irq_counter = irq_latch;
//					nes->cpu->IRQ();
					nes->cpu->SetIRQ( IRQ_MAPPER );
				}
			}
		}
	}
}

void	Mapper100::SetBank_CPU()
{
	SetPROM_32K_Bank( prg0, prg1, prg2, prg3 );
}

void	Mapper100::SetBank_PPU()
{
	if( VROM_1K_SIZE ) {
		SetVROM_8K_Bank( chr0, chr1, chr2, chr3, chr4, chr5, chr6, chr7 );
	}
}

void	Mapper100::SaveState( LPBYTE p )
{
	for( INT i = 0; i < 8; i++ ) {
		p[i] = reg[i];
	}
	p[ 8] = prg0;
	p[ 9] = prg1;
	p[10] = prg2;
	p[11] = prg3;
	p[12] = chr0;
	p[13] = chr1;
	p[14] = chr2;
	p[15] = chr3;
	p[16] = chr4;
	p[17] = chr5;
	p[18] = chr6;
	p[19] = chr7;
	p[20] = irq_enable;
	p[21] = irq_counter;
	p[22] = irq_latch;
}

void	Mapper100::LoadState( LPBYTE p )
{
	for( INT i = 0; i < 8; i++ ) {
		reg[i] = p[i];
	}
	prg0  = p[ 8];
	prg1  = p[ 9];
	prg2  = p[10];
	prg3  = p[11];
	chr0  = p[12];
	chr1  = p[13];
	chr2  = p[14];
	chr3  = p[15];
	chr4  = p[16];
	chr5  = p[17];
	chr6  = p[18];
	chr7  = p[19];
	irq_enable  = p[20];
	irq_counter = p[21];
	irq_latch   = p[22];
}