mappers/16.c

   1 /* FCE Ultra - NES/Famicom Emulator
   2  *
   3  * Copyright notice for this file:
   4  *  Copyright (C) 1998 BERO
   5  *  Copyright (C) 2002 Ben Parnell
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #include "mapinc.h"
  23
  24 static void FP_FASTAPASS(1) BandaiIRQHook(int a)
  25 {
  26   if(IRQa)
  27   {
  28    IRQCount-=a;
  29    if(IRQCount<0)
  30    {
  31     X6502_IRQBegin(FCEU_IQEXT);
  32     //printf("IRQ: %d, %d\n",scanline,timestamp);
  33     IRQa=0;
  34     IRQCount=0xFFFF;
  35    }
  36   }
  37 }
  38
  39 static DECLFW(Mapper16_write)
  40 {
  41         A&=0xF;
  42
  43         if(A<=0x7)
  44          VROM_BANK1(A<<10,V);
  45         else if(A==0x8)
  46         {
  47          ROM_BANK16(0x8000,V);
  48          X6502_Rebase();
  49         }
  50         else switch(A) {
  51          case 0x9: switch(V&3) {
  52                     case 0x00:MIRROR_SET2(1);break;
  53                     case 0x01:MIRROR_SET2(0);break;
  54                     case 0x02:onemir(0);break;
  55                     case 0x03:onemir(1);break;
  56                    }
  57                    break;
  58          case 0xA:X6502_IRQEnd(FCEU_IQEXT);
  59                   IRQa=V&1;
  60                   IRQCount=IRQLatch;
  61                   break;
  62          case 0xB:IRQLatch&=0xFF00;
  63                   IRQLatch|=V;
  64                   break;
  65          case 0xC:IRQLatch&=0xFF;
  66                   IRQLatch|=V<<8;
  67                   break;
  68          case 0xD: break;/* Serial EEPROM control port */
  69  }
  70 }
  71
  72 // Famicom jump 2:
  73 // 0-7: Lower bit of data selects which 256KB PRG block is in use.
  74 // This seems to be a hack on the developers' part, so I'll make emulation
  75 // of it a hack(I think the current PRG block would depend on whatever the
  76 // lowest bit of the CHR bank switching register that corresponds to the
  77 // last CHR address read).
  78
  79 static void PRGO(void)
  80 {
  81  uint32 base=(mapbyte1[0]&1)<<4;
  82  ROM_BANK16(0x8000,(mapbyte2[0]&0xF)|base);
  83  ROM_BANK16(0xC000,base|0xF);
  84  X6502_Rebase();
  85 }
  86
  87 static DECLFW(Mapper153_write)
  88 {
  89         A&=0xF;
  90         if(A<=0x7)
  91         {
  92          mapbyte1[A&7]=V;
  93          PRGO();
  94         }
  95         else if(A==0x8)
  96         {
  97          mapbyte2[0]=V;
  98          PRGO();
  99         }
 100         else switch(A) {
 101          case 0x9: switch(V&3) {
 102                     case 0x00:MIRROR_SET2(1);break;
 103                     case 0x01:MIRROR_SET2(0);break;
 104                     case 0x02:onemir(0);break;
 105                     case 0x03:onemir(1);break;
 106                    }
 107                    break;
 108          case 0xA:X6502_IRQEnd(FCEU_IQEXT);
 109                   IRQa=V&1;
 110                   IRQCount=IRQLatch;
 111                   break;
 112          case 0xB:IRQLatch&=0xFF00;
 113                   IRQLatch|=V;
 114                   break;
 115          case 0xC:IRQLatch&=0xFF;
 116                   IRQLatch|=V<<8;
 117                   break;
 118         }
 119 }
 120
 121 void Mapper16_init(void)
 122 {
 123  MapIRQHook=BandaiIRQHook;
 124  SetWriteHandler(0x6000,0xFFFF,Mapper16_write);
 125 }
 126
 127 void Mapper153_init(void)
 128 {
 129  MapIRQHook=BandaiIRQHook;
 130  SetWriteHandler(0x8000,0xFFFF,Mapper153_write);
 131  /* This mapper/board seems to have WRAM at $6000-$7FFF, so I'll let the
 132     main ines code take care of that memory region. */
 133 }