103 lines
2.4 KiB
C
103 lines
2.4 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) 2005 CaH4e3
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* Copyright (C) 2020
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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 uint16 cmdreg;
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static uint8 unrom, reg, openbus;
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static uint32 PRGROMSize;
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static SFORMAT StateRegs[] =
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{
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{ &cmdreg, 2 | FCEUSTATE_RLSB, "CREG" },
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{ &unrom, 1, "UNRM" },
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{ ®, 1, "UNRG" },
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{ &openbus, 1, "OPNB" },
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{ 0 }
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};
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static void Sync(void) {
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if (unrom) {
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uint8 PRGPageSize = PRGROMSize / 16384;
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setprg16(0x8000, (PRGPageSize & 0xC0) | (reg & 7));
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setprg16(0xC000, (PRGPageSize & 0xC0) | 7);
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setchr8(0);
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setmirror(MI_V);
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} else {
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uint8 bank = ((cmdreg & 0x300) >> 3) | (cmdreg & 0x1F);
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if (cmdreg & 0x400)
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setmirror(MI_0);
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else
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setmirror(((cmdreg >> 13) & 1) ^ 1);
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if (bank >= PRGROMSize / 32768)
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openbus = 1;
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else if (cmdreg & 0x800) {
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setprg16(0x8000, (bank << 1) | ((cmdreg >> 12) & 1));
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setprg16(0xC000, (bank << 1) | ((cmdreg >> 12) & 1));
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} else
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setprg32(0x8000, bank);
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setchr8(0);
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}
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}
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static DECLFR(M235Read) {
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if (openbus) {
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openbus = 0;
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return X.DB;
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}
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return CartBR(A);
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}
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static DECLFW(M235Write) {
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cmdreg = A;
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reg = V;
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Sync();
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}
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static void M235Reset(void) {
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cmdreg = 0;
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reg = 0;
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if (PRGROMSize & 0x20000)
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unrom = (unrom + 1) & 1;
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Sync();
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}
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static void M235Power(void) {
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SetWriteHandler(0x8000, 0xFFFF, M235Write);
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SetReadHandler(0x8000, 0xFFFF, M235Read);
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cmdreg = 0;
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reg = 0;
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Sync();
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}
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static void M235Restore(int version) {
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Sync();
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}
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void Mapper235_Init(CartInfo *info) {
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info->Reset = M235Reset;
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info->Power = M235Power;
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GameStateRestore = M235Restore;
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AddExState(&StateRegs, ~0, 0, 0);
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PRGROMSize = info->PRGRomSize;
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}
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