mappers/25.c

   1 /* FCE Ultra - NES/Famicom Emulator
   2  *
   3  * Copyright notice for this file:
   4  *  Copyright (C) 2002 Ben Parnell
   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
  21 #include "mapinc.h"
  22
  23 #define K4buf mapbyte2
  24 #define K4IRQ mapbyte1[1]
  25 #define K4sel mapbyte1[0]
  26
  27 DECLFW(Mapper25_write)
  28 {
  29         A=(A&0xF003)|((A&0xC)>>2);
  30
  31         if((A&0xF000)==0xA000)
  32           ROM_BANK8(0xA000,V);
  33         else if(A>=0xB000 && A<=0xEFFF)
  34         {
  35          int x=(A&1)|((A-0xB000)>>11);
  36
  37          K4buf[x]&=(0xF0)>>((A&2)<<1);
  38          K4buf[x]|=(V&0xF)<<((A&2)<<1);
  39          VROM_BANK1(x<<10,K4buf[x]);
  40         }
  41         else if((A&0xF000)==0x8000)
  42         {
  43          if(K4sel&2)
  44           ROM_BANK8(0xC000,V);
  45          else
  46           ROM_BANK8(0x8000,V);
  47         }
  48         else switch(A)
  49         {
  50          case 0x9000:switch(V&0x3)
  51                      {
  52                       case 0:MIRROR_SET(0);break;
  53                       case 1:MIRROR_SET(1);break;
  54                       case 2:onemir(0);break;
  55                       case 3:onemir(1);break;
  56                      }
  57                      break;
  58          case 0x9001:if((K4sel&2)!=(V&2))
  59                      {
  60                       uint8 swa;
  61                       swa=PRGBankList[0];
  62                       ROM_BANK8(0x8000,PRGBankList[2]);
  63                       ROM_BANK8(0xc000,swa);
  64                      }
  65                      K4sel=V;
  66                      break;
  67         case 0xf000:IRQLatch&=0xF0;IRQLatch|=V&0xF;break;
  68         case 0xf002:IRQLatch&=0x0F;IRQLatch|=V<<4;break;
  69         case 0xf001:IRQCount=IRQLatch;IRQa=V&2;K4IRQ=V&1;break;
  70         case 0xf003:IRQa=K4IRQ;break;
  71  }
  72 }
  73
  74 static void FP_FASTAPASS(1) KonamiIRQHook(int a)
  75 {
  76   static int count=0;
  77   #define LCYCS 114
  78   if(IRQa)
  79   {
  80    count+=a;
  81    if(count>=LCYCS)
  82    {
  83     doagainbub:count-=LCYCS;IRQCount++;
  84     if(IRQCount&0x100) {count=0;TriggerIRQ();IRQCount=IRQLatch;}
  85     if(count>=LCYCS) goto doagainbub;
  86    }
  87  }
  88 }
  89
  90 void Mapper25_init(void)
  91 {
  92         SetWriteHandler(0x8000,0xffff,Mapper25_write);
  93         MapIRQHook=KonamiIRQHook;
  94 }
  95