AxibugEmuOnline/virtuanessrc097-master/NES/Mapper/Mapper142.cpp

76 lines
3.4 KiB
C++
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

//////////////////////////////////////////////////////////////////////////
// Mapper142 SMB2j Pirate (KS 202) //
//////////////////////////////////////////////////////////////////////////
void Mapper142::Reset()
{
prg_sel = 0;
irq_enable = 0;
irq_counter = 0;
SetPROM_8K_Bank( 3, 0 );
SetPROM_8K_Bank( 7, 0x0F );
if( VROM_1K_SIZE ) {
SetVROM_8K_Bank( 0 );
}
}
void Mapper142::Write( WORD 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 = data & 0x0F;
nes->cpu->ClrIRQ( IRQ_MAPPER );
break;
case 0xE000:
prg_sel = 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 )
{
if( irq_enable ) {
if( irq_counter > (0xFFFF - 113) ) {
irq_counter = 0;
nes->cpu->SetIRQ( IRQ_MAPPER );
} else {
irq_counter += 113;
}
}
}
void Mapper142::SaveState( LPBYTE p )
{
p[0] = prg_sel;
p[0] = irq_enable;
*(INT*)&p[2] = irq_counter;
}
void Mapper142::LoadState( LPBYTE p )
{
prg_sel = p[0];
irq_enable = p[1];
irq_counter = *(INT*)&p[2];
}