126 lines
3.1 KiB
C
126 lines
3.1 KiB
C
/* FCEUmm - NES/Famicom Emulator
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*
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* Copyright notice for this file:
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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
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (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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/* NES 2.0 Mapper 357 is used for a 4-in-1 multicart (cartridge ID 4602) from Bit Corp.
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* The first game is Bit Corp's hack of the YUNG-08 conversion of Super Mario Brothers 2 (J) named Mr. Mary 2,
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* the other three games are UNROM games.
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*
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* Implementation is modified so reset actually sets the correct dipswitch (or outer banks) for each of the 4 games
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*/
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#include "mapinc.h"
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static uint8 preg[4];
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static uint8 dipswitch;
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static uint8 IRQa;
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static uint16 IRQCount;
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static const uint8 banks[8] = { 4, 3, 5, 3, 6, 3, 7, 3 };
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static const uint8 outer_bank[4] = { 0x00, 0x08, 0x10, 0x18 };
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static SFORMAT StateRegs[] =
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{
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{ &IRQCount, 2 | FCEUSTATE_RLSB, "IRQC" },
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{ &IRQa, 1 | FCEUSTATE_RLSB, "IRQA" },
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{ &dipswitch, 1, "DPSW" },
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{ &preg, 4, "REG" },
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{ 0 }
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};
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static void Sync(void) {
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if (dipswitch == 0) {
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/* SMB2J Mode */
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setprg4(0x5000, 16);
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setprg8(0x6000, preg[1] ? 0 : 2);
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setprg8(0x8000, 1);
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setprg8(0xa000, 0);
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setprg8(0xc000, banks[preg[0]]);
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setprg8(0xe000, preg[1] ? 8 : 10);
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} else {
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/* UNROM Mode */
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setprg16(0x8000, outer_bank[dipswitch] | preg[2]);
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setprg16(0xc000, outer_bank[dipswitch] | 7);
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}
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setchr8(0);
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setmirror(dipswitch == 3 ? MI_H : MI_V);
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}
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static DECLFW(M357WriteLo) {
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switch (A & 0x71ff) {
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case 0x4022: preg[0] = V & 7; Sync(); break;
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case 0x4120: preg[1] = V & 1; Sync(); break;
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}
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}
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static DECLFW(M357WriteIRQ) {
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IRQa = V & 1;
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if (!IRQa) {
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IRQCount = 0;
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X6502_IRQEnd(FCEU_IQEXT);
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}
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}
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static DECLFW(M357WriteUNROM) {
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preg[2] = V & 7;
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Sync();
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}
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static void M357Power(void) {
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preg[0] = 0;
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preg[1] = 0;
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IRQa = IRQCount = 0;
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Sync();
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SetReadHandler(0x5000, 0xffff, CartBR);
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SetWriteHandler(0x4022, 0x4022, M357WriteLo);
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SetWriteHandler(0x4120, 0x4120, M357WriteLo);
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SetWriteHandler(0x4122, 0x4122, M357WriteIRQ);
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SetWriteHandler(0x8000, 0xffff, M357WriteUNROM);
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}
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static void M357Reset(void) {
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IRQa = IRQCount = 0;
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dipswitch++;
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dipswitch &= 3;
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Sync();
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}
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static void FP_FASTAPASS(1) M357IRQHook(int a) {
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if (IRQa) {
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if (IRQCount < 4096)
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IRQCount += a;
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else {
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IRQa = 0;
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X6502_IRQBegin(FCEU_IQEXT);
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}
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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 Mapper357_Init(CartInfo *info) {
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info->Reset = M357Reset;
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info->Power = M357Power;
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MapIRQHook = M357IRQHook;
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GameStateRestore = StateRestore;
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AddExState(&StateRegs, ~0, 0, 0);
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}
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