c62d2810 |
1 | /* FCE Ultra - NES/Famicom Emulator |
2 | * |
3 | * Copyright notice for this file: |
d97315ac |
4 | * Copyright (C) 2002 Xodnizel |
c62d2810 |
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 |
43725da7 |
18 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
c62d2810 |
19 | */ |
20 | |
21 | #include "mapinc.h" |
22 | |
386f5371 |
23 | //16 bits of ram in total |
24 | //only use bottom 4 bits as ram though |
25 | static uint8 mapper228_ram[4]; |
26 | |
386f5371 |
27 | static DECLFR(Mapper228_read) |
28 | { |
29 | return mapper228_ram[A & 3] & 0xF; |
30 | } |
31 | |
c62d2810 |
32 | static DECLFW(Mapper228_write) |
33 | { |
43725da7 |
34 | uint32 page,pagel,pageh; |
c62d2810 |
35 | |
386f5371 |
36 | //write to ram |
37 | if (A < 0x6000) |
38 | { |
39 | mapper228_ram[A & 3] = V; |
40 | return; |
41 | } |
43725da7 |
42 | MIRROR_SET((A>>13)&1); |
43 | page=(A>>7)&0x3F; |
c62d2810 |
44 | |
43725da7 |
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; |
c62d2810 |
50 | |
43725da7 |
51 | ROM_BANK16(0x8000,pagel); |
52 | ROM_BANK16(0xC000,pageh); |
53 | VROM_BANK8( (V&0x3) | ((A&0xF)<<2) ); |
c62d2810 |
54 | } |
55 | |
56 | static void A52Reset(void) |
57 | { |
386f5371 |
58 | Mapper228_write(0x8000, 0); |
c62d2810 |
59 | } |
60 | |
61 | void Mapper228_init(void) |
62 | { |
43725da7 |
63 | MapperReset=A52Reset; |
64 | A52Reset(); |
386f5371 |
65 | SetWriteHandler(0x8000, 0xFFFF, Mapper228_write); |
66 | SetWriteHandler(0x4020, 0x5FFF, Mapper228_write); |
67 | SetReadHandler (0x4020, 0x5FFF, Mapper228_read); |
43725da7 |
68 | AddExState(mapper228_ram, 4, 0, "MRAM"); |
c62d2810 |
69 | } |
70 | |