AxibugEmuOnline/References/virtuanessrc097-master/NES/Mapper/Mapper042.cpp
2024-08-05 17:58:53 +08:00

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//////////////////////////////////////////////////////////////////////////
// Mapper042 Mario Baby //
//////////////////////////////////////////////////////////////////////////
void Mapper042::Reset()
{
irq_enable = 0;
irq_counter = 0;
SetPROM_8K_Bank( 3, 0 );
SetPROM_32K_Bank( PROM_8K_SIZE-4, PROM_8K_SIZE-3, PROM_8K_SIZE-2, PROM_8K_SIZE-1 );
if( VROM_1K_SIZE ) {
SetVROM_8K_Bank( 0 );
}
}
void Mapper042::Write( WORD addr, BYTE data )
{
switch( addr & 0xE003 ) {
case 0xE000:
SetPROM_8K_Bank( 3, data&0x0F );
break;
case 0xE001:
if( data&0x08 ) SetVRAM_Mirror( VRAM_HMIRROR );
else SetVRAM_Mirror( VRAM_VMIRROR );
break;
case 0xE002:
if( data&0x02 ) {
irq_enable = 0xFF;
} else {
irq_enable = 0;
irq_counter = 0;
}
nes->cpu->ClrIRQ( IRQ_MAPPER );
break;
}
}
void Mapper042::HSync( INT scanline )
{
nes->cpu->ClrIRQ( IRQ_MAPPER );
if( irq_enable ) {
if( irq_counter < 215 ) {
irq_counter++;
}
if( irq_counter == 215 ) {
irq_enable = 0;
// nes->cpu->IRQ();
nes->cpu->SetIRQ( IRQ_MAPPER );
}
}
}
void Mapper042::SaveState( LPBYTE p )
{
p[0] = irq_enable;
p[1] = irq_counter;
}
void Mapper042::LoadState( LPBYTE p )
{
irq_enable = p[0];
irq_counter = p[1];
}