105 lines
2.8 KiB
C
105 lines
2.8 KiB
C
/* FCEUmm - NES/Famicom Emulator
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*
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* Copyright (C) 2019 Libretro Team
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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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/* added 2019-5-23
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* BMC-WS Used for Super 40-in-1 multicart
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* https://wiki.nesdev.com/w/index.php/NES_2.0_Mapper_332 */
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#include "mapinc.h"
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static uint8 preg, creg, latch, dipSwitch;
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static SFORMAT StateRegs[] =
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{
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{ &preg, 1, "PREG" },
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{ &creg, 1, "CREG" },
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{ &latch, 1, "LATC" },
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{ &dipSwitch, 1, "DPSW" },
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{ 0 }
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};
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static void Sync(void) {
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int prg = (preg & 7) | ((preg >> 3) & 0x08); /* There is a high bit 3 of the PRG register that applies both to PRG and CHR */
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int chr = (creg & 7) | ((preg >> 3) & 0x08); /* There is a high bit 3 of the PRG register that applies both to PRG and CHR */
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int mask = (creg & 0x10)? 0: (creg & 0x20)? 1: 3; /* There is an CNROM mode that takes either two or four inner CHR banks from a CNROM-like latch register at $8000-$FFFF. */
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if (preg & 8) {
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setprg16(0x8000, prg);
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setprg16(0xc000, prg);
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}
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else
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setprg32(0x8000, prg >> 1);
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setchr8((chr &~mask) | (latch &mask)); /* This "inner CHR bank" substitutes the respective bit(s) of the creg register. */
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setmirror(((preg >> 4) & 1) ^ 1);
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}
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static DECLFR(BMCWSRead) {
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if ((creg >> 6) & (dipSwitch &3))
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return X.DB;
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return CartBR(A);
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}
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static DECLFW(BMCWSWrite) {
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if (preg & 0x20)
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return;
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switch (A & 1) {
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case 0: preg = V; Sync(); break;
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case 1: creg = V; Sync(); break;
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}
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}
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static DECLFW(LatchWrite) {
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latch =V;
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Sync();
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}
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static void MBMCWSPower(void) {
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dipSwitch =0;
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Sync();
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SetReadHandler(0x8000, 0xFFFF, BMCWSRead);
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SetWriteHandler(0x6000, 0x7FFF, BMCWSWrite);
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SetWriteHandler(0x8000, 0xFFFF, LatchWrite);
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}
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static void BMCWSReset(void) {
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dipSwitch++; /* Soft-resetting cycles through solder pad or DIP switch settings */
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if (dipSwitch == 3)
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dipSwitch = 0; /* Only 00b, 01b and 10b settings are valid */
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/* Always reset to menu */
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preg =0;
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creg =0;
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latch =0;
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Sync();
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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 BMCWS_Init(CartInfo *info) {
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info->Reset = BMCWSReset;
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info->Power = MBMCWSPower;
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GameStateRestore = StateRestore;
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AddExState(&StateRegs, ~0, 0, 0);
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}
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