mappers/21.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
  21 #include "mapinc.h"
  22
  23 #define K4buf mapbyte2
  24 #define K4IRQ mapbyte1[1]
  25 #define K4sel mapbyte1[0]
  26
  27 static int acount=0;
  28
  29 DECLFW(Mapper21_write)
  30 {
  31         A|=((A>>5)&0xF);
  32
  33         if((A&0xF000)==0xA000)
  34           ROM_BANK8(0xA000,V);
  35         else if((A&0xF000)==0x8000)
  36         {
  37          if(K4sel&2)
  38           ROM_BANK8(0xC000,V);
  39          else
  40           ROM_BANK8(0x8000,V);
  41          }
  42         else if(A>=0xb000 && A<=0xefff)
  43         {
  44           A&=0xF006;
  45           {
  46            int x=((A>>2)&1)|((A-0xB000)>>11);
  47
  48            K4buf[x]&=(0xF0)>>((A&2)<<1);
  49            K4buf[x]|=(V&0xF)<<((A&2)<<1);
  50            VROM_BANK1(x<<10,K4buf[x]);
  51           }
  52
  53         }
  54         else switch(A&0xF006)
  55         {
  56          case 0x9000:
  57                      switch(V&0x3)
  58                      {
  59                       case 0:MIRROR_SET(0);break;
  60                       case 1:MIRROR_SET(1);break;
  61                       case 2:onemir(0);break;
  62                       case 3:onemir(1);break;
  63                       }
  64                      break;
  65          case 0x9006:
  66          case 0x9004:
  67          case 0x9002:if((K4sel&2)!=(V&2))
  68                      {
  69                            uint8 swa;
  70                       swa=PRGBankList[0];
  71                        ROM_BANK8(0x8000,PRGBankList[2]);
  72                       ROM_BANK8(0xc000,swa);
  73                       }
  74                      K4sel=V;
  75                      break;
  76          case 0xf000:IRQLatch&=0xF0;IRQLatch|=V&0xF;break;
  77          case 0xf002:IRQLatch&=0x0F;IRQLatch|=V<<4;break;
  78          case 0xf004:IRQCount=IRQLatch;acount=0;
  79                      IRQa=V&2;K4IRQ=V&1;
  80                      X6502_IRQEnd(FCEU_IQEXT);
  81                      break;
  82          case 0xf006:IRQa=K4IRQ;X6502_IRQEnd(FCEU_IQEXT);break;
  83  }
  84 }
  85 static void FP_FASTAPASS(1) KonamiIRQHook(int a)
  86 {
  87   #define LCYCS ((227*2)+1)
  88   //#define LCYCS 341
  89   if(IRQa)
  90   {
  91 //    acount+=a*3;
  92     acount+=a*4;
  93     if(acount>=LCYCS)
  94     {
  95      doagainbub:acount-=LCYCS;IRQCount++;
  96      if(IRQCount&0x100) {X6502_IRQBegin(FCEU_IQEXT);IRQCount=IRQLatch;}
  97      if(acount>=LCYCS) goto doagainbub;
  98     }
  99  }
 100 }
 101
 102 void Mapper21_init(void)
 103 {
 104         SetWriteHandler(0x8000,0xffff,Mapper21_write);
 105         MapIRQHook=KonamiIRQHook;
 106 }