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/*===================================================================*/
/* */
/* Mapper 78 (74161/32 Irem) */
/* */
/*===================================================================*/
/*-------------------------------------------------------------------*/
/* Initialize Mapper 78 */
/*-------------------------------------------------------------------*/
void Map78_Init()
{
/* Initialize Mapper */
MapperInit = Map78_Init;
/* Write to Mapper */
MapperWrite = Map78_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();
}
/* Set up wiring of the interrupt pin */
K6502_Set_Int_Wiring( 1, 1 );
}
/*-------------------------------------------------------------------*/
/* Mapper 78 Write Function */
/*-------------------------------------------------------------------*/
void Map78_Write( WORD wAddr, BYTE byData )
{
BYTE byPrgBank = byData & 0x0f;
BYTE byChrBank = ( byData & 0xf0 ) >> 4;
/* Set ROM Banks */
byPrgBank <<= 1;
byPrgBank %= ( NesHeader.byRomSize << 1 );
ROMBANK0 = ROMPAGE( byPrgBank );
ROMBANK1 = ROMPAGE( byPrgBank + 1);
/* Set PPU Banks */
byChrBank <<= 3;
byChrBank %= ( NesHeader.byVRomSize << 3 );
PPUBANK[ 0 ] = VROMPAGE( byChrBank );
PPUBANK[ 1 ] = VROMPAGE( byChrBank + 1 );
PPUBANK[ 2 ] = VROMPAGE( byChrBank + 2 );
PPUBANK[ 3 ] = VROMPAGE( byChrBank + 3 );
PPUBANK[ 4 ] = VROMPAGE( byChrBank + 4 );
PPUBANK[ 5 ] = VROMPAGE( byChrBank + 5 );
PPUBANK[ 6 ] = VROMPAGE( byChrBank + 6 );
PPUBANK[ 7 ] = VROMPAGE( byChrBank + 7 );
InfoNES_SetupChr();
/* Set Name Table Mirroring */
if ( ( wAddr & 0xfe00 ) != 0xfe00 )
{
if ( byData & 0x08 )
{
InfoNES_Mirroring( 2 );
} else {
InfoNES_Mirroring( 3 );
}
}
}
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