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/*===================================================================*/
/* */
/* Mapper 24 (Konami VRC6) */
/* */
/*===================================================================*/
BYTE Map24_IRQ_Count;
BYTE Map24_IRQ_State;
BYTE Map24_IRQ_Latch;
/*-------------------------------------------------------------------*/
/* Initialize Mapper 24 */
/*-------------------------------------------------------------------*/
void Map24_Init()
{
/* Initialize Mapper */
MapperInit = Map24_Init;
/* Write to Mapper */
MapperWrite = Map24_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 = Map24_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 up wiring of the interrupt pin */
K6502_Set_Int_Wiring( 1, 1 );
}
/*-------------------------------------------------------------------*/
/* Mapper 24 Write Function */
/*-------------------------------------------------------------------*/
void Map24_Write( WORD wAddr, BYTE byData )
{
switch ( wAddr )
{
case 0x8000:
/* Set ROM Banks */
ROMBANK0 = ROMPAGE( ( byData + 0 ) % ( NesHeader.byRomSize << 1) );
ROMBANK1 = ROMPAGE( ( byData + 1 ) % ( NesHeader.byRomSize << 1) );
break;
case 0xb003:
/* Name Table Mirroring */
switch ( byData & 0x0c )
{
case 0x00:
InfoNES_Mirroring( 1 ); /* Vertical */
break;
case 0x04:
InfoNES_Mirroring( 0 ); /* Horizontal */
break;
case 0x08:
InfoNES_Mirroring( 3 ); /* One Screen 0x2000 */
break;
case 0x0c:
InfoNES_Mirroring( 2 ); /* One Screen 0x2400 */
break;
}
break;
case 0xC000:
ROMBANK2 = ROMPAGE( byData % ( NesHeader.byRomSize << 1) );
break;
case 0xD000:
PPUBANK[ 0 ] = VROMPAGE( byData % ( NesHeader.byVRomSize << 3 ) );
InfoNES_SetupChr();
break;
case 0xD001:
PPUBANK[ 1 ] = VROMPAGE( byData % ( NesHeader.byVRomSize << 3 ) );
InfoNES_SetupChr();
break;
case 0xD002:
PPUBANK[ 2 ] = VROMPAGE( byData % ( NesHeader.byVRomSize << 3 ) );
InfoNES_SetupChr();
break;
case 0xD003:
PPUBANK[ 3 ] = VROMPAGE( byData % ( NesHeader.byVRomSize << 3 ) );
InfoNES_SetupChr();
break;
case 0xE000:
PPUBANK[ 4 ] = VROMPAGE( byData % ( NesHeader.byVRomSize << 3 ) );
InfoNES_SetupChr();
break;
case 0xE001:
PPUBANK[ 5 ] = VROMPAGE( byData % ( NesHeader.byVRomSize << 3 ) );
InfoNES_SetupChr();
break;
case 0xE002:
PPUBANK[ 6 ] = VROMPAGE( byData % ( NesHeader.byVRomSize << 3 ) );
InfoNES_SetupChr();
break;
case 0xE003:
PPUBANK[ 7 ] = VROMPAGE( byData % ( NesHeader.byVRomSize << 3 ) );
InfoNES_SetupChr();
break;
case 0xF000:
Map24_IRQ_Latch = byData;
break;
case 0xF001:
Map24_IRQ_State = byData & 0x03;
if(Map24_IRQ_State & 0x02)
{
Map24_IRQ_Count = Map24_IRQ_Latch;
}
break;
case 0xF002:
if(Map24_IRQ_State & 0x01)
{
Map24_IRQ_State |= 0x02;
}
else
{
Map24_IRQ_State &= 0x01;
}
break;
}
}
/*-------------------------------------------------------------------*/
/* Mapper 24 H-Sync Function */
/*-------------------------------------------------------------------*/
void Map24_HSync()
{
/*
* Callback at HSync
*
*/
if(Map24_IRQ_State & 0x02)
{
if(Map24_IRQ_Count == 0xFF)
{
IRQ_REQ;
Map24_IRQ_Count = Map24_IRQ_Latch;
}
else
{
Map24_IRQ_Count++;
}
}
}
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