68 lines
1.8 KiB
C
68 lines
1.8 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) 2023
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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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*/
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#include "mapinc.h"
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#include "latch.h"
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static uint8 reg[2];
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static SFORMAT StateRegs[] = {
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{ reg, 2, "REGS" },
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{ 0 }
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};
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static void Sync(void) {
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uint8 mask = (8 << (reg[1] >> 4 & 3)) - 1;
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setprg4(0x7000, 0);
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if (reg[1] & 6)
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setprg32(0x8000, (reg[0] << 2) + (latch.data & (mask >> 1)));
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else {
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setprg16(0x8000, (reg[0] << 3) + (latch.data & mask));
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setprg16(0xC000, (reg[0] << 3) + mask);
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}
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setchr8(0);
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if (reg[1] & 2) {
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setmirror(MI_0 + (latch.data >> 4) & 1);
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} else {
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setmirror(reg[1] & 1);
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}
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}
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static DECLFW(M502WriteReg) {
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if (~reg[1] & 0x80) {
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reg[A & 1] = V;
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Sync();
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}
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}
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static void M502Power() {
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reg[0] = reg[1] = 0;
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LatchPower();
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SetReadHandler(0x7000, 0x7FFF, CartBR);
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SetWriteHandler(0x6000, 0x6FFF, M502WriteReg);
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}
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void Mapper502_Init(CartInfo *info) {
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Latch_Init(info, Sync, NULL, 0, 0);
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info->Power = M502Power;
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AddExState(StateRegs, ~0, 0, NULL);
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}
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