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/*===================================================================*/
/* */
/* Mapper 75 (Konami VRC 1 and Jaleco SS8805) */
/* */
/*===================================================================*/
BYTE Map75_Regs[ 2 ];
/*-------------------------------------------------------------------*/
/* Initialize Mapper 75 */
/*-------------------------------------------------------------------*/
void Map75_Init()
{
/* Initialize Mapper */
MapperInit = Map75_Init;
/* Write to Mapper */
MapperWrite = Map75_Write;
/* Write to SRAM */
MapperSram = Map0_Sram;
/* Write to APU */
MapperApu = Map0_Apu;
/* Read from APU */
MapperReadApu = Map0_ReadApu;
/* Callback at VSync */
MapperVSync = Map0_VSync;
/* Callback at HSync */
MapperHSync = Map0_HSync;
/* Callback at PPU */
MapperPPU = Map0_PPU;
/* Callback at Rendering Screen ( 1:BG, 0:Sprite ) */
MapperRenderScreen = Map0_RenderScreen;
/* Set SRAM Banks */
SRAMBANK = SRAM;
/* Set ROM Banks */
ROMBANK0 = ROMPAGE( 0 );
ROMBANK1 = ROMPAGE( 1 );
ROMBANK2 = ROMLASTPAGE( 1 );
ROMBANK3 = ROMLASTPAGE( 0 );
/* Set PPU Banks */
if ( NesHeader.byVRomSize > 0 )
{
for ( int nPage = 0; nPage < 8; ++nPage )
PPUBANK[ nPage ] = VROMPAGE( nPage );
InfoNES_SetupChr();
}
/* Initialize State Flag */
Map75_Regs[ 0 ] = 0;
Map75_Regs[ 1 ] = 1;
/* Set up wiring of the interrupt pin */
K6502_Set_Int_Wiring( 1, 1 );
}
/*-------------------------------------------------------------------*/
/* Mapper 75 Write Function */
/*-------------------------------------------------------------------*/
void Map75_Write( WORD wAddr, BYTE byData )
{
switch ( wAddr & 0xf000 )
{
/* Set ROM Banks */
case 0x8000:
byData %= ( NesHeader.byRomSize << 1 );
ROMBANK0 = ROMPAGE( byData );
break;
case 0x9000:
/* Set Mirroring */
if ( byData & 0x01 )
{
InfoNES_Mirroring( 0 );
} else {
InfoNES_Mirroring( 1 );
}
/* Set PPU Banks */
Map75_Regs[ 0 ] = ( Map75_Regs[ 0 ] & 0x0f ) | ( ( byData & 0x02 ) << 3 );
PPUBANK[ 0 ] = VROMPAGE( ( Map75_Regs[ 0 ] << 2 ) + 0 );
PPUBANK[ 1 ] = VROMPAGE( ( Map75_Regs[ 0 ] << 2 ) + 1 );
PPUBANK[ 2 ] = VROMPAGE( ( Map75_Regs[ 0 ] << 2 ) + 2 );
PPUBANK[ 3 ] = VROMPAGE( ( Map75_Regs[ 0 ] << 2 ) + 3 );
Map75_Regs[ 1 ] = ( Map75_Regs[ 1 ] & 0x0f ) | ( ( byData & 0x04 ) << 2 );
PPUBANK[ 4 ] = VROMPAGE( ( Map75_Regs[ 1 ] << 2 ) + 0 );
PPUBANK[ 5 ] = VROMPAGE( ( Map75_Regs[ 1 ] << 2 ) + 1 );
PPUBANK[ 6 ] = VROMPAGE( ( Map75_Regs[ 1 ] << 2 ) + 2 );
PPUBANK[ 7 ] = VROMPAGE( ( Map75_Regs[ 1 ] << 2 ) + 3 );
InfoNES_SetupChr();
break;
/* Set ROM Banks */
case 0xA000:
byData %= ( NesHeader.byRomSize << 1 );
ROMBANK1 = ROMPAGE( byData );
break;
/* Set ROM Banks */
case 0xC000:
byData %= ( NesHeader.byRomSize << 1 );
ROMBANK2 = ROMPAGE( byData );
break;
case 0xE000:
/* Set PPU Banks */
Map75_Regs[ 0 ] = ( Map75_Regs[ 0 ] & 0x10 ) | ( byData & 0x0f );
PPUBANK[ 0 ] = VROMPAGE( ( Map75_Regs[ 0 ] << 2 ) + 0 );
PPUBANK[ 1 ] = VROMPAGE( ( Map75_Regs[ 0 ] << 2 ) + 1 );
PPUBANK[ 2 ] = VROMPAGE( ( Map75_Regs[ 0 ] << 2 ) + 2 );
PPUBANK[ 3 ] = VROMPAGE( ( Map75_Regs[ 0 ] << 2 ) + 3 );
InfoNES_SetupChr();
break;
case 0xF000:
/* Set PPU Banks */
Map75_Regs[ 1 ] = ( Map75_Regs[ 1 ] & 0x10 ) | ( byData & 0x0f );
PPUBANK[ 4 ] = VROMPAGE( ( Map75_Regs[ 1 ] << 2 ) + 0 );
PPUBANK[ 5 ] = VROMPAGE( ( Map75_Regs[ 1 ] << 2 ) + 1 );
PPUBANK[ 6 ] = VROMPAGE( ( Map75_Regs[ 1 ] << 2 ) + 2 );
PPUBANK[ 7 ] = VROMPAGE( ( Map75_Regs[ 1 ] << 2 ) + 3 );
InfoNES_SetupChr();
break;
}
}
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