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56 lines
1.3 KiB
C
56 lines
1.3 KiB
C
/* Is this an MMC3 workalike piece of hardware, with the addition of
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a register at $4120 or does it have only partial MMC3 functionality?
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A good test would be to see if commands 6 and 7 can change PRG banks
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and of course test the regs >=$c000, on the real cart.
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*/
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#include "mapinc.h"
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#define cmd mapbyte1[0]
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static DECLFW(Mapper189_write)
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{
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//if(A>=0xc000) printf("$%04x:$%02x\n",A,V);
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if((A&0xF100)==0x4100) ROM_BANK32(V>>4);
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else if((A&0xF100)==0x6100) ROM_BANK32(V&3);
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else switch(A&0xE001)
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{
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case 0xa000:MIRROR_SET(V&1);break;
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case 0x8000:cmd=V;break;
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case 0x8001:switch(cmd&7)
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{
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case 0:VROM_BANK2(0x0000,V>>1);break;
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case 1:VROM_BANK2(0x0800,V>>1);break;
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case 2:VROM_BANK1(0x1000,V);break;
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case 3:VROM_BANK1(0x1400,V);break;
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case 4:VROM_BANK1(0x1800,V);break;
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case 5:VROM_BANK1(0x1C00,V);break;
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}
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case 0xc000:IRQLatch=V;break;
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case 0xc001:IRQCount=IRQLatch;break;
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case 0xe000:IRQa=0;X6502_IRQEnd(FCEU_IQEXT);break;
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case 0xe001:IRQa=1;break;
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break;
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}
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}
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void m189irq(void)
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{
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if(IRQa)
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{
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if(IRQCount)
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{
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IRQCount--;
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if(!IRQCount) X6502_IRQBegin(FCEU_IQEXT);
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}
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}
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}
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void Mapper189_init(void)
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{
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GameHBIRQHook=m189irq;
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SetWriteHandler(0x4120,0xFFFF,Mapper189_write);
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SetReadHandler(0x6000,0x7FFF,0);
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ROM_BANK32(0);
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}
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