mirror of
https://github.com/dborth/fceugx.git
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77 lines
1.9 KiB
C++
77 lines
1.9 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) 2002 Xodnizel
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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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "mapinc.h"
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//16 bits of ram in total
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//only use bottom 4 bits as ram though
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static uint8 mapper228_ram[4];
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static SFORMAT StateRegs[]=
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{
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{ mapper228_ram, 4, "MAPPER_RAM" },
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{ 0 }
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};
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static DECLFR(Mapper228_read)
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{
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return mapper228_ram[A & 3] & 0xF;
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}
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static DECLFW(Mapper228_write)
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{
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uint32 page, pagel, pageh;
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//write to ram
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if (A < 0x6000)
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{
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mapper228_ram[A & 3] = V;
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return;
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}
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MIRROR_SET((A >> 13) & 1);
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page = (A >> 7) & 0x3F;
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if( (page & 0x30) == 0x30)
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page -= 0x10;
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pagel = pageh = (page << 1) + (((A >> 6) & 1) & ((A >> 5) & 1));
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pageh += ((A >> 5) & 1) ^ 1;
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ROM_BANK16(0x8000,pagel);
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ROM_BANK16(0xC000,pageh);
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VROM_BANK8( (V&0x3) | ((A&0xF)<<2) );
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}
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static void A52Reset(void)
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{
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Mapper228_write(0x8000, 0);
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}
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void Mapper228_init(void)
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{
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MapperReset=A52Reset;
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A52Reset();
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SetWriteHandler(0x8000, 0xFFFF, Mapper228_write);
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SetWriteHandler(0x4020, 0x5FFF, Mapper228_write);
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SetReadHandler (0x4020, 0x5FFF, Mapper228_read);
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AddExState(StateRegs, ~0, 0, 0);
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}
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