fceux/mappers/73.c

61 lines
1.6 KiB
C

/* FCE Ultra - NES/Famicom Emulator
*
* Copyright notice for this file:
* Copyright (C) 2002 Xodnizel
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "mapinc.h"
static DECLFW(Mapper73_write)
{
//if(A>=0xd000 && A<=0xdfff)
X6502_IRQEnd(FCEU_IQEXT); /* How are IRQs acknowledged on this chip? */
switch(A&0xF000)
{
//default: printf("$%04x:$%02x\n",A,V);break;
case 0x8000:IRQCount&=0xFFF0;IRQCount|=(V&0xF);break;
case 0x9000:IRQCount&=0xFF0F;IRQCount|=(V&0xF)<<4;break;
case 0xa000:IRQCount&=0xF0FF;IRQCount|=(V&0xF)<<8;break;
case 0xb000:IRQCount&=0x0FFF;IRQCount|=(V&0xF)<<12;break;
case 0xc000:IRQa=V&2;break;
case 0xf000:ROM_BANK16(0x8000,V);break;
}
}
static void FP_FASTAPASS(1) Mapper73IRQHook(int a)
{
if(IRQa)
{
IRQCount+=a;
if(IRQCount>=0xFFFF)
{
IRQCount&=0xFFFF;
IRQa=0;
X6502_IRQBegin(FCEU_IQEXT);
}
}
}
void Mapper73_init(void)
{
SetWriteHandler(0x8000,0xffff,Mapper73_write);
MapIRQHook=Mapper73IRQHook;
}