| 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 | { |
| 11 | if(A==0x4120) |
| 12 | { |
| 13 | ROM_BANK32(V>>4); |
| 14 | X6502_Rebase(); |
| 15 | } |
| 16 | else switch(A&0xE001) |
| 17 | { |
| 18 | case 0xa000:MIRROR_SET(V&1);break; |
| 19 | case 0x8000:cmd=V;break; |
| 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 | |