mirror of
https://github.com/dborth/fceugx.git
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84 lines
2.2 KiB
C++
84 lines
2.2 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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* FDS Conversion
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*
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*/
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#include "mapinc.h"
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static uint8 preg, creg, mirr;
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static uint32 IRQCount, IRQa;
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static SFORMAT StateRegs[] =
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{
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{ &preg, 1, "PREG" },
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{ &creg, 1, "CREG" },
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{ &mirr, 1, "MIRR" },
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{ &IRQCount, 4, "IRQC" },
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{ &IRQa, 4, "IRQA" },
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{ 0 }
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};
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static void Sync(void) {
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setprg8(0x6000, preg);
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setprg32(0x8000, ~0);
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setchr8(creg);
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setmirror(mirr);
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}
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static DECLFW(M42Write) {
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switch (A & 0xE003) {
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case 0x8000: creg = V; Sync(); break;
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case 0xE000: preg = V & 0x0F; Sync(); break;
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case 0xE001: mirr = ((V >> 3) & 1 ) ^ 1; Sync(); break;
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case 0xE002: IRQa = V & 2; if (!IRQa) IRQCount = 0; X6502_IRQEnd(FCEU_IQEXT); break;
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}
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}
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static void M42Power(void) {
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preg = 0;
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mirr = 1; // Ai Senshi Nicol actually has fixed mirroring, but mapper forcing it's default value now
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Sync();
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SetReadHandler(0x6000, 0xffff, CartBR);
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SetWriteHandler(0x6000, 0xffff, M42Write);
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}
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static void M42IRQHook(int a) {
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if (IRQa) {
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IRQCount += a;
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if (IRQCount >= 32768) IRQCount -= 32768;
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if (IRQCount >= 24576)
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X6502_IRQBegin(FCEU_IQEXT);
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else
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X6502_IRQEnd(FCEU_IQEXT);
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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 Mapper42_Init(CartInfo *info) {
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info->Power = M42Power;
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MapIRQHook = M42IRQHook;
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GameStateRestore = StateRestore;
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AddExState(&StateRegs, ~0, 0, 0);
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}
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