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/*===================================================================*/
/* */
/* Mapper 26 (Konami VRC 6V) */
/* */
/*===================================================================*/
BYTE Map26_IRQ_Enable;
BYTE Map26_IRQ_Cnt;
BYTE Map26_IRQ_Latch;
/*-------------------------------------------------------------------*/
/* Initialize Mapper 26 */
/*-------------------------------------------------------------------*/
void Map26_Init()
{
int nPage;
/* Initialize Mapper */
MapperInit = Map26_Init;
/* Write to Mapper */
MapperWrite = Map26_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 = Map26_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 ( nPage = 0; nPage < 8; ++nPage )
PPUBANK[ nPage ] = VROMPAGE( nPage );
InfoNES_SetupChr();
}
/* Initialize IRQ Registers */
Map26_IRQ_Enable = 0;
Map26_IRQ_Cnt = 0;
/* Set up wiring of the interrupt pin */
K6502_Set_Int_Wiring( 1, 1 );
}
/*-------------------------------------------------------------------*/
/* Mapper 26 Write Function */
/*-------------------------------------------------------------------*/
void Map26_Write( WORD wAddr, BYTE byData )
{
switch ( wAddr )
{
/* Set ROM Banks */
case 0x8000:
byData <<= 1;
byData %= ( NesHeader.byRomSize << 1 );
ROMBANK0 = ROMPAGE( byData + 0 );
ROMBANK1 = ROMPAGE( byData + 1 );
break;
/* Name Table Mirroring */
case 0xb003:
switch ( byData & 0x7f )
{
case 0x08:
case 0x2c:
InfoNES_Mirroring( 2 ); /* One Screen 0x2400 */
break;
case 0x20:
InfoNES_Mirroring( 1 ); /* Vertical */
break;
case 0x24:
InfoNES_Mirroring( 0 ); /* Horizontal */
break;
case 0x28:
InfoNES_Mirroring( 3 ); /* One Screen 0x2000 */
break;
}
break;
/* Set ROM Banks */
case 0xc000:
byData %= ( NesHeader.byRomSize << 1 );
ROMBANK2 = ROMPAGE( byData );
InfoNES_SetupChr();
break;
/* Set PPU Bank */
case 0xd000:
byData %= ( NesHeader.byVRomSize << 3 );
PPUBANK[ 0 ] = VROMPAGE( byData );
InfoNES_SetupChr();
break;
case 0xd001:
byData %= ( NesHeader.byVRomSize << 3 );
PPUBANK[ 2 ] = VROMPAGE( byData );
InfoNES_SetupChr();
break;
case 0xd002:
byData %= ( NesHeader.byVRomSize << 3 );
PPUBANK[ 1 ] = VROMPAGE( byData );
InfoNES_SetupChr();
break;
case 0xd003:
byData %= ( NesHeader.byVRomSize << 3 );
PPUBANK[ 3 ] = VROMPAGE( byData );
InfoNES_SetupChr();
break;
case 0xe000:
byData %= ( NesHeader.byVRomSize << 3 );
PPUBANK[ 4 ] = VROMPAGE( byData );
InfoNES_SetupChr();
break;
case 0xe001:
byData %= ( NesHeader.byVRomSize << 3 );
PPUBANK[ 6 ] = VROMPAGE( byData );
InfoNES_SetupChr();
break;
case 0xe002:
byData %= ( NesHeader.byVRomSize << 3 );
PPUBANK[ 5 ] = VROMPAGE( byData );
InfoNES_SetupChr();
break;
case 0xe003:
byData %= ( NesHeader.byVRomSize << 3 );
PPUBANK[ 7 ] = VROMPAGE( byData );
InfoNES_SetupChr();
break;
/* Set IRQ Registers */
case 0xf000:
Map26_IRQ_Latch = byData;
break;
case 0xf001:
Map26_IRQ_Enable = byData & 0x01;
break;
case 0xf002:
Map26_IRQ_Enable = byData & 0x03;
if ( Map26_IRQ_Enable & 0x02 )
{
Map26_IRQ_Cnt = Map26_IRQ_Latch;
}
break;
}
}
/*-------------------------------------------------------------------*/
/* Mapper 26 H-Sync Function */
/*-------------------------------------------------------------------*/
void Map26_HSync()
{
/*
* Callback at HSync
*
*/
if ( Map26_IRQ_Enable & 0x03 )
{
if ( Map26_IRQ_Cnt >= 0xfe )
{
IRQ_REQ;
Map26_IRQ_Cnt = Map26_IRQ_Latch;
Map26_IRQ_Enable = 0;
} else {
Map26_IRQ_Cnt++;
}
}
}
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