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/*===================================================================*/
/* */
/* Mapper 42 (Pirates) */
/* */
/*===================================================================*/
BYTE Map42_IRQ_Cnt;
BYTE Map42_IRQ_Enable;
/*-------------------------------------------------------------------*/
/* Initialize Mapper 42 */
/*-------------------------------------------------------------------*/
void Map42_Init()
{
/* Initialize Mapper */
MapperInit = Map42_Init;
/* Write to Mapper */
MapperWrite = Map42_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 = Map42_HSync;
/* Callback at PPU */
MapperPPU = Map0_PPU;
/* Callback at Rendering Screen ( 1:BG, 0:Sprite ) */
MapperRenderScreen = Map0_RenderScreen;
/* Set SRAM Banks */
SRAMBANK = ROMPAGE( 0 );
/* Set ROM Banks */
ROMBANK0 = ROMLASTPAGE( 3 );
ROMBANK1 = ROMLASTPAGE( 2 );
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 42 Write Function */
/*-------------------------------------------------------------------*/
void Map42_Write( WORD wAddr, BYTE byData )
{
switch ( wAddr & 0xe003 )
{
/* Set ROM Banks */
case 0xe000:
SRAMBANK = ROMPAGE( ( byData & 0x0f ) % ( NesHeader.byRomSize << 1 ) );
break;
case 0xe001:
if ( byData & 0x08 )
{
InfoNES_Mirroring( 0 );
} else {
InfoNES_Mirroring( 1 );
}
break;
case 0xe002:
if ( byData & 0x02 )
{
Map42_IRQ_Enable = 1;
} else {
Map42_IRQ_Enable = 0;
Map42_IRQ_Cnt = 0;
}
break;
}
}
/*-------------------------------------------------------------------*/
/* Mapper 42 H-Sync Function */
/*-------------------------------------------------------------------*/
void Map42_HSync()
{
/*
* Callback at HSync
*
*/
if ( Map42_IRQ_Enable )
{
if ( Map42_IRQ_Cnt < 215 )
{
Map42_IRQ_Cnt++;
}
if ( Map42_IRQ_Cnt == 215 )
{
IRQ_REQ;
Map42_IRQ_Enable = 0;
}
}
}
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