| 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 | //16 bits of ram in total |
| 24 | //only use bottom 4 bits as ram though |
| 25 | static uint8 mapper228_ram[4]; |
| 26 | |
| 27 | static DECLFR(Mapper228_read) |
| 28 | { |
| 29 | return mapper228_ram[A & 3] & 0xF; |
| 30 | } |
| 31 | |
| 32 | static DECLFW(Mapper228_write) |
| 33 | { |
| 34 | uint32 page,pagel,pageh; |
| 35 | |
| 36 | //write to ram |
| 37 | if (A < 0x6000) |
| 38 | { |
| 39 | mapper228_ram[A & 3] = V; |
| 40 | return; |
| 41 | } |
| 42 | MIRROR_SET((A>>13)&1); |
| 43 | page=(A>>7)&0x3F; |
| 44 | |
| 45 | if((page&0x30)==0x30) |
| 46 | page-=0x10; |
| 47 | |
| 48 | pagel=pageh=(page<<1) + (((A>>6)&1)&((A>>5)&1)); |
| 49 | pageh+=((A>>5)&1)^1; |
| 50 | |
| 51 | ROM_BANK16(0x8000,pagel); |
| 52 | ROM_BANK16(0xC000,pageh); |
| 53 | VROM_BANK8( (V&0x3) | ((A&0xF)<<2) ); |
| 54 | } |
| 55 | |
| 56 | static void A52Reset(void) |
| 57 | { |
| 58 | Mapper228_write(0x8000, 0); |
| 59 | } |
| 60 | |
| 61 | void Mapper228_init(void) |
| 62 | { |
| 63 | MapperReset=A52Reset; |
| 64 | A52Reset(); |
| 65 | SetWriteHandler(0x8000, 0xFFFF, Mapper228_write); |
| 66 | SetWriteHandler(0x4020, 0x5FFF, Mapper228_write); |
| 67 | SetReadHandler (0x4020, 0x5FFF, Mapper228_read); |
| 68 | AddExState(mapper228_ram, 4, 0, "MRAM"); |
| 69 | } |
| 70 | |