| 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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 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 | } |