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1 | /* Is this an MMC3 workalike piece of hardware, with the addition of |
2 | a register at $4120 or does it have only partial MMC3 functionality? |
3 | A good test would be to see if commands 6 and 7 can change PRG banks |
4 | and of course test the regs >=$c000, on the real cart. |
5 | */ |
6 | #include "mapinc.h" |
7 | |
8 | #define cmd mapbyte1[0] |
9 | static DECLFW(Mapper189_write) |
10 | { |
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11 | if(A==0x4120) |
12 | { |
13 | ROM_BANK32(V>>4); |
14 | X6502_Rebase(); |
15 | } |
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16 | else switch(A&0xE001) |
17 | { |
18 | case 0xa000:MIRROR_SET(V&1);break; |
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19 | case 0x8000:cmd=V;break; |
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20 | case 0x8001:switch(cmd&7) |
21 | { |
22 | case 0:VROM_BANK2(0x0000,V>>1);break; |
23 | case 1:VROM_BANK2(0x0800,V>>1);break; |
24 | case 2:VROM_BANK1(0x1000,V);break; |
25 | case 3:VROM_BANK1(0x1400,V);break; |
26 | case 4:VROM_BANK1(0x1800,V);break; |
27 | case 5:VROM_BANK1(0x1C00,V);break; |
28 | } |
29 | break; |
30 | |
31 | } |
32 | } |
33 | |
34 | void Mapper189_init(void) |
35 | { |
36 | SetWriteHandler(0x4120,0xFFFF,Mapper189_write); |
37 | SetReadHandler(0x6000,0x7FFF,0); |
38 | ROM_BANK32(0); |
39 | } |
40 | |
41 | |