mappers/42.c

   1 /* FCE Ultra - NES/Famicom Emulator
   2  *
   3  * Copyright notice for this file:
   4  *  Copyright (C) 2002 Xodnizel
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  *
  20  * FDS Conversion
  21  *
  22  */
  23
  24 #include "mapinc.h"
  25
  26
  27 static DECLFW(Mapper42_write)
  28 {
  29 // FCEU_printf("%04x:%04x\n",A,V);
  30  switch(A&0xe003)
  31  {
  32   case 0x8000:VROM_BANK8(V);break;
  33   case 0xe000:mapbyte1[0]=V;ROM_BANK8(0x6000,V&0xF);break;
  34   case 0xe001:MIRROR_SET((V>>3)&1);break;
  35   case 0xe002:IRQa=V&2;if(!IRQa) IRQCount=0;X6502_IRQEnd(FCEU_IQEXT);break;
  36  }
  37 }
  38
  39 static void FP_FASTAPASS(1) Mapper42IRQ(int a)
  40 {
  41  if(IRQa)
  42  {
  43         IRQCount+=a;
  44         if(IRQCount>=32768) IRQCount-=32768;
  45         if(IRQCount>=24576)
  46          X6502_IRQBegin(FCEU_IQEXT);
  47         else
  48          X6502_IRQEnd(FCEU_IQEXT);
  49  }
  50 }
  51
  52 static void Mapper42_StateRestore(int version)
  53 {
  54     ROM_BANK8(0x6000,mapbyte1[0]&0xF);
  55 }
  56
  57
  58 void Mapper42_init(void)
  59 {
  60   ROM_BANK8(0x6000,0);
  61   ROM_BANK32(~0);
  62   SetWriteHandler(0x6000,0xffff,Mapper42_write);
  63   SetReadHandler(0x6000,0x7fff,CartBR);
  64   MapStateRestore=Mapper42_StateRestore;
  65   MapIRQHook=Mapper42IRQ;
  66 }
  67