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/*===================================================================*/
/* */
/* Mapper 68 (Sunsoft Mapper #4) */
/* */
/*===================================================================*/
BYTE Map68_Regs[4];
/*-------------------------------------------------------------------*/
/* Initialize Mapper 68 */
/*-------------------------------------------------------------------*/
void Map68_Init()
{
/* Initialize Mapper */
MapperInit = Map68_Init;
/* Write to Mapper */
MapperWrite = Map68_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 );
/* Initialize state flag */
for ( int i = 0; i < 4; i++ )
Map68_Regs[ i ] = 0x00;
/* Set up wiring of the interrupt pin */
K6502_Set_Int_Wiring( 1, 1 );
}
/*-------------------------------------------------------------------*/
/* Mapper 68 Write Function */
/*-------------------------------------------------------------------*/
void Map68_Write( WORD wAddr, BYTE byData )
{
switch( wAddr )
{
case 0x8000:
/* Set PPU Banks */
byData %= ( NesHeader.byVRomSize << 2 );
byData <<= 1;
PPUBANK[ 0 ] = VROMPAGE( byData );
PPUBANK[ 1 ] = VROMPAGE( byData + 1);
InfoNES_SetupChr();
break;
case 0x9000:
/* Set PPU Banks */
byData %= ( NesHeader.byVRomSize << 2 );
byData <<= 1;
PPUBANK[ 2 ] = VROMPAGE( byData );
PPUBANK[ 3 ] = VROMPAGE( byData + 1);
InfoNES_SetupChr();
break;
case 0xA000:
/* Set PPU Banks */
byData %= ( NesHeader.byVRomSize << 2 );
byData <<= 1;
PPUBANK[ 4 ] = VROMPAGE( byData );
PPUBANK[ 5 ] = VROMPAGE( byData + 1);
InfoNES_SetupChr();
break;
case 0xB000:
/* Set PPU Banks */
byData %= ( NesHeader.byVRomSize << 2 );
byData <<= 1;
PPUBANK[ 6 ] = VROMPAGE( byData );
PPUBANK[ 7 ] = VROMPAGE( byData + 1);
InfoNES_SetupChr();
break;
case 0xC000:
Map68_Regs[ 2 ] = byData;
Map68_SyncMirror();
break;
case 0xD000:
Map68_Regs[ 3 ] = byData;
Map68_SyncMirror();
break;
case 0xE000:
Map68_Regs[ 0 ] = ( byData & 0x10 ) >> 4;
Map68_Regs[ 1 ] = byData & 0x03;
Map68_SyncMirror();
break;
case 0xF000:
/* Set ROM Banks */
byData %= NesHeader.byRomSize;
byData <<= 1;
ROMBANK0 = ROMPAGE( byData );
ROMBANK1 = ROMPAGE( byData + 1 );
break;
}
}
/*-------------------------------------------------------------------*/
/* Mapper 68 Sub Function */
/*-------------------------------------------------------------------*/
void Map68_SyncMirror( void )
{
if ( Map68_Regs[ 0 ] )
{
switch( Map68_Regs[ 1 ] )
{
case 0x00:
PPUBANK[ 8 ] = VROMPAGE( Map68_Regs[ 2 ] + 0x80 );
PPUBANK[ 9 ] = VROMPAGE( Map68_Regs[ 3 ] + 0x80 );
PPUBANK[ 10 ] = VROMPAGE( Map68_Regs[ 2 ] + 0x80 );
PPUBANK[ 11 ] = VROMPAGE( Map68_Regs[ 3 ] + 0x80 );
break;
case 0x01:
PPUBANK[ 8 ] = VROMPAGE( Map68_Regs[ 2 ] + 0x80 );
PPUBANK[ 9 ] = VROMPAGE( Map68_Regs[ 2 ] + 0x80 );
PPUBANK[ 10 ] = VROMPAGE( Map68_Regs[ 3 ] + 0x80 );
PPUBANK[ 11 ] = VROMPAGE( Map68_Regs[ 3 ] + 0x80 );
break;
case 0x02:
PPUBANK[ 8 ] = VROMPAGE( Map68_Regs[ 2 ] + 0x80 );
PPUBANK[ 9 ] = VROMPAGE( Map68_Regs[ 2 ] + 0x80 );
PPUBANK[ 10 ] = VROMPAGE( Map68_Regs[ 2 ] + 0x80 );
PPUBANK[ 11 ] = VROMPAGE( Map68_Regs[ 2 ] + 0x80 );
break;
case 0x03:
PPUBANK[ 8 ] = VROMPAGE( Map68_Regs[ 3 ] + 0x80 );
PPUBANK[ 9 ] = VROMPAGE( Map68_Regs[ 3 ] + 0x80 );
PPUBANK[ 10 ] = VROMPAGE( Map68_Regs[ 3 ] + 0x80 );
PPUBANK[ 11 ] = VROMPAGE( Map68_Regs[ 3 ] + 0x80 );
break;
}
InfoNES_SetupChr();
}
else
{
InfoNES_Mirroring( Map68_Regs[ 1 ] );
}
}
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