mappers/25.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  * (VRC4 mapper)
  20  */
  21
  22 #include "mapinc.h"
  23
  24 #define K4buf mapbyte2
  25 #define K4IRQ mapbyte1[1]
  26 #define K4sel mapbyte1[0]
  27
  28 static int acount=0;
  29 static int weirdo=0;
  30 static DECLFW(Mapper25_write)
  31 {
  32         if(A==0xC007)
  33                 {
  34                         weirdo=8; // Ganbare Goemon Gaiden does strange things!!! at the end credits
  35                               // quick dirty hack, seems there is no other games with such PCB, so
  36                               // we never know if it will not work for something else lol
  37                         VROM_BANK1(0x0000,0xFC);
  38                         VROM_BANK1(0x0400,0xFD);
  39                         VROM_BANK1(0x0800,0xFF);
  40                 }
  41
  42         A=(A&0xF003)|((A&0xC)>>2);
  43
  44         if((A&0xF000)==0xA000)
  45           ROM_BANK8(0xA000,V);
  46         else if(A>=0xB000 && A<=0xEFFF)
  47         {
  48          int x=(A&1)|((A-0xB000)>>11);
  49
  50          K4buf[x]&=(0xF0)>>((A&2)<<1);
  51          K4buf[x]|=(V&0xF)<<((A&2)<<1);
  52                  if(weirdo)
  53           weirdo--;
  54                  else
  55            VROM_BANK1(x<<10,K4buf[x]);
  56         }
  57         else if((A&0xF000)==0x8000)
  58         {
  59          if(K4sel&2)
  60           ROM_BANK8(0xC000,V);
  61          else
  62           ROM_BANK8(0x8000,V);
  63         }
  64         else switch(A)
  65         {
  66          case 0x9000:switch(V&0x3)
  67                      {
  68                       case 0:MIRROR_SET(0);break;
  69                       case 1:MIRROR_SET(1);break;
  70                       case 2:onemir(0);break;
  71                       case 3:onemir(1);break;
  72                       }
  73                      break;
  74          case 0x9001:if((K4sel&2)!=(V&2))
  75                      {
  76                            uint8 swa;
  77                       swa=PRGBankList[0];
  78                        ROM_BANK8(0x8000,PRGBankList[2]);
  79                       ROM_BANK8(0xc000,swa);
  80                      }
  81                      K4sel=V;
  82                      break;
  83         case 0xf000:IRQLatch&=0xF0;IRQLatch|=V&0xF;break;
  84         case 0xf002:IRQLatch&=0x0F;IRQLatch|=V<<4;break;
  85         case 0xf001:IRQCount=IRQLatch;IRQa=V&2;K4IRQ=V&1;acount=0;X6502_IRQEnd(FCEU_IQEXT);break;
  86         case 0xf003:IRQa=K4IRQ;X6502_IRQEnd(FCEU_IQEXT);break;
  87  }
  88 }
  89
  90 static void FP_FASTAPASS(1) KonamiIRQHook(int a)
  91 {
  92 //  #define LCYCS ((227*2))
  93   #define LCYCS 341
  94   if(IRQa)
  95   {
  96    acount+=a*3;
  97   // acount+=a*4;
  98    if(acount>=LCYCS)
  99    {
 100     doagainbub:acount-=LCYCS;IRQCount++;
 101     if(IRQCount&0x100)
 102     {//acount=0;
 103      X6502_IRQBegin(FCEU_IQEXT);IRQCount=IRQLatch;
 104         }
 105     if(acount>=LCYCS) goto doagainbub;
 106    }
 107  }
 108 }
 109
 110 void Mapper25_init(void)
 111 {
 112         SetWriteHandler(0x8000,0xffff,Mapper25_write);
 113         MapIRQHook=KonamiIRQHook;
 114 }
 115