mirror of
https://github.com/dborth/fceugx.git
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122 lines
2.9 KiB
C++
122 lines
2.9 KiB
C++
/* FCE Ultra - NES/Famicom Emulator
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*
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* Copyright notice for this file:
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* Copyright (C) 2012 CaH4e3
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "mapinc.h"
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static uint8 preg[4], creg[8];
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static uint8 IRQa, mirr;
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static int32 IRQCount, IRQLatch;
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static SFORMAT StateRegs[]=
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{
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{preg, 4, "PREG"},
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{creg, 8, "CREG"},
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{&mirr, 1, "MIRR"},
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{&IRQa, 1, "IRQA"},
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{&IRQCount, 4, "IRQC"},
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{&IRQLatch, 4, "IRQL"},
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{0}
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};
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static void Sync(void)
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{
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int i;
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for(i=0; i<8; i++) setchr1(i<<10,creg[i]);
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setprg8(0x8000,preg[0]);
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setprg8(0xA000,preg[1]);
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setprg8(0xC000,preg[2]);
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setprg8(0xE000,~0);
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if(mirr & 2)
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setmirror(MI_0);
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else
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setmirror(mirr & 1);
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}
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static DECLFW(M18WriteIRQ)
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{
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switch(A & 0xF003) {
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case 0xE000: IRQLatch&=0xFFF0; IRQLatch|=(V&0x0f)<<0x0;break;
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case 0xE001: IRQLatch&=0xFF0F; IRQLatch|=(V&0x0f)<<0x4; break;
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case 0xE002: IRQLatch&=0xF0FF; IRQLatch|=(V&0x0f)<<0x8; break;
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case 0xE003: IRQLatch&=0x0FFF; IRQLatch|=(V&0x0f)<<0xC; break;
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case 0xF000: IRQCount=IRQLatch; break;
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case 0xF001: IRQa=V&1; X6502_IRQEnd(FCEU_IQEXT); break;
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case 0xF002: mirr = V&3; Sync(); break;
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}
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}
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static DECLFW(M18WritePrg)
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{
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uint32 i = ((A >> 1) & 1)|((A - 0x8000) >> 11);
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preg[i] &= (0xF0) >> ((A & 1) << 2);
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preg[i] |= (V & 0xF) << ((A & 1) << 2);
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Sync();
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}
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static DECLFW(M18WriteChr)
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{
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uint32 i = ((A >> 1) & 1)|((A - 0xA000) >> 11);
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creg[i] &= (0xF0) >> ((A & 1) << 2);
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creg[i] |= (V & 0xF) << ((A & 1) << 2);
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Sync();
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}
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static void M18Power(void)
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{
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preg[0] = 0;
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preg[1] = 1;
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preg[2] = ~1;
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preg[3] = ~0;
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Sync();
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SetReadHandler(0x8000,0xFFFF,CartBR);
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SetWriteHandler(0x8000,0x9FFF,M18WritePrg);
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SetWriteHandler(0xA000,0xDFFF,M18WriteChr);
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SetWriteHandler(0xE000,0xFFFF,M18WriteIRQ);
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}
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static void M18IRQHook(int a)
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{
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if(IRQa && IRQCount)
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{
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IRQCount-=a;
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if(IRQCount<=0)
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{
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X6502_IRQBegin(FCEU_IQEXT);
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IRQCount=0;
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IRQa=0;
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}
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}
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}
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static void StateRestore(int version)
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{
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Sync();
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}
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void Mapper18_Init(CartInfo *info)
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{
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info->Power=M18Power;
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MapIRQHook=M18IRQHook;
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GameStateRestore=StateRestore;
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AddExState(&StateRegs, ~0, 0, 0);
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}
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