64 lines
2.0 KiB
C
64 lines
2.0 KiB
C
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/* FCEUmm - 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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#include "mapinc.h"
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#include "mmc3.h"
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static void M420CW(uint32 A, uint8 V) {
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uint8 mask = (EXPREGS[1] & 0x80) ? 0x7F : 0xFF;
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setchr1(A, ((EXPREGS[1] << 1) & 0x100) | ((EXPREGS[1] << 5) & 0x80) | (V & mask));
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}
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static void M420PW(uint32 A, uint8 V) {
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if (EXPREGS[0] & 0x80) {
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setprg32(0x8000, ((EXPREGS[2] >> 2) & 8) | ((EXPREGS[0] >> 1) & 7));
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} else {
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uint8 mask = (EXPREGS[0] & 0x20) ? 0x0F : ((EXPREGS[3] & 0x20) ? 0x1F : 0x3F);
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setprg8(A, ((EXPREGS[3] << 3) & 0x20) | (V & mask));
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}
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}
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static DECLFW(M420Write) {
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/* writes possible regardless of MMC3 wram state */
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EXPREGS[A & 3] = V;
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FixMMC3PRG(MMC3_cmd);
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FixMMC3CHR(MMC3_cmd);
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}
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static void M420Reset(void) {
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EXPREGS[0] = EXPREGS[1] = EXPREGS[2] = EXPREGS[3] = 0;
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MMC3RegReset();
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}
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static void M420Power(void) {
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EXPREGS[0] = EXPREGS[1] = EXPREGS[2] = EXPREGS[3] = 0;
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GenMMC3Power();
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SetWriteHandler(0x6000, 0x7FFF, M420Write);
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}
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void Mapper420_Init(CartInfo *info) {
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GenMMC3_Init(info, 512, 256, 0, 0);
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cwrap = M420CW;
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pwrap = M420PW;
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info->Reset = M420Reset;
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info->Power = M420Power;
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AddExState(EXPREGS, 4, 0, "EXPR");
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}
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