mirror of
https://github.com/dborth/fceugx.git
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112 lines
2.9 KiB
C++
112 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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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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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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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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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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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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if (IRQa && IRQCount) {
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IRQCount -= a;
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if (IRQCount <= 0) {
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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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Sync();
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}
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void Mapper18_Init(CartInfo *info) {
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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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