mapper105.cpp

著名的任天堂FC游戏机模拟器VirtuaNes 085版的源码!

//////////////////////////////////////////////////////////////////////////
// Mapper105  Nintendo World Championship                               //
//////////////////////////////////////////////////////////////////////////

void	Mapper105::Reset()
{
	SetPROM_32K_Bank( 0 );

	reg[0] = 0x0C;
	reg[1] = 0x00;
	reg[2] = 0x00;
	reg[3] = 0x10;

	bits = 0;
	write_count = 0;

	irq_counter = 0;
	irq_enable = 0;
	init_state = 0;
}

void	Mapper105::Write( WORD addr, BYTE data )
{
	WORD reg_num = (addr & 0x7FFF) >> 13;

	if( data & 0x80 ) {
		bits = write_count = 0;
		if( reg_num == 0 ) {
			reg[reg_num] |= 0x0C;
		}
	} else {
		bits |= (data & 1) << write_count++;
		if( write_count == 5) {
			reg[reg_num] = bits & 0x1F;
			bits = write_count = 0;
		}
	}

	if( reg[0] & 0x02 ) {
		if( reg[0] & 0x01 ) {
			SetVRAM_Mirror( VRAM_HMIRROR );
		} else {
			SetVRAM_Mirror( VRAM_VMIRROR );
		}
	} else {
		if( reg[0] & 0x01 ) {
			SetVRAM_Mirror( VRAM_MIRROR4H );
		} else {
			SetVRAM_Mirror( VRAM_MIRROR4L );
		}
	}

	switch( init_state ) {
		case 0:
		case 1:
			init_state++;
			break;
		case 2:
			if(reg[1] & 0x08) {
				if (reg[0] & 0x08) {
					if (reg[0] & 0x04) {
						SetPROM_8K_Bank(4,((reg[3] & 0x07) * 2 + 16));
						SetPROM_8K_Bank(5,((reg[3] & 0x07) * 2 + 17));
						SetPROM_8K_Bank(6,30);
						SetPROM_8K_Bank(7,31);
					} else {
						SetPROM_8K_Bank(4,16);
						SetPROM_8K_Bank(5,17);
						SetPROM_8K_Bank(6,((reg[3] & 0x07) * 2 + 16));
						SetPROM_8K_Bank(7,((reg[3] & 0x07) * 2 + 17));
					}
				} else {
					SetPROM_8K_Bank(4,((reg[3] & 0x06) * 2 + 16));
					SetPROM_8K_Bank(5,((reg[3] & 0x06) * 2 + 17));
					SetPROM_8K_Bank(6,((reg[3] & 0x06) * 2 + 18));
					SetPROM_8K_Bank(7,((reg[3] & 0x06) * 2 + 19));
				}
			} else {
				SetPROM_8K_Bank(4,((reg[1] & 0x06) * 2 + 0));
				SetPROM_8K_Bank(5,((reg[1] & 0x06) * 2 + 1));
				SetPROM_8K_Bank(6,((reg[1] & 0x06) * 2 + 2));
				SetPROM_8K_Bank(7,((reg[1] & 0x06) * 2 + 3));
			}

			if( reg[1] & 0x10 ) {
				irq_counter = 0;
				irq_enable = 0;
			} else {
				irq_enable = 1;
			}
//			nes->cpu->ClrIRQ( IRQ_MAPPER );
			break;
		default:
			break;
	}
}

void	Mapper105::HSync( INT scanline )
{
	if( !scanline ) {
		if( irq_enable ) {
			irq_counter += 29781;
		}
		if( ((irq_counter | 0x21FFFFFF) & 0x3E000000) == 0x3E000000 ) {
//			nes->cpu->IRQ_NotPending();
//			nes->cpu->SetIRQ( IRQ_MAPPER );
			nes->cpu->SetIRQ( IRQ_TRIGGER2 );
		}
	}
}

void	Mapper105::SaveState( LPBYTE p )
{
	for( INT i = 0; i < 4; i++ ) {
		p[i] = reg[i];
	}
	p[ 8] = init_state;
	p[ 9] = write_count;
	p[10] = bits;
	p[11] = irq_enable;
	*((INT*)&p[12]) = irq_counter;
}

void	Mapper105::LoadState( LPBYTE p )
{
	for( INT i = 0; i < 4; i++ ) {
		reg[i] = p[i];
	}
	init_state  = p[ 8];
	write_count = p[ 9];
	bits        = p[10];
	irq_enable  = p[11];
	irq_counter = *((INT*)&p[12]);
}