101 lines
2.7 KiB
C
101 lines
2.7 KiB
C
/* FCE Ultra - NES/Famicom Emulator
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*
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* Copyright notice for this file: 2025 NewRisingSun
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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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*/
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#include "mapinc.h"
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static uint8 reg[2];
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static uint8 submapper;
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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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int prg =(reg[1] &0x40? (reg[0] >>3 &1): (reg[1] &0x01)) |
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reg[1] &0x3E;
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int chr = reg[0] &0x03 |
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(reg[1] &0x40? (reg[0] &0x04): (reg[1] <<2 &4)) |
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reg[1] <<2 &0xF8;
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if (prg &0x30) prg -=0x10; /* The register layout assumes a 2 MiB address space. The first ROM chip is only 512 KiB though, and the .NES file is not padded or repeated to fill those 2 MiB. */
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if (chr &0xC0) chr -=0x40; /* Therefore, subtract 512 KiB from the PRG and CHR outer bank if anything after the first 512 KiB is selected. */
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setprg32(0x8000, prg);
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setchr8(chr);
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setmirror(reg[1] &0x80? MI_H: MI_V);
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}
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static DECLFW(WriteNINA_Prototype) {
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if (A &0x200)
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reg[1] =V;
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else
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if (A &0x100)
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reg[0] =V;
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Sync();
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}
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static DECLFW(WriteNINA08) {
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if (A &0x100) {
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if (A &0x080) /* Second register is always writable */
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reg[1] =V;
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else
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if (~reg[1] &0x20) /* First register is only writable in NINA-03 mode */
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reg[0] =V;
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Sync();
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}
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Sync();
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}
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static DECLFW(WriteColorDreams) {
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if (reg[1] &0x20) { /* Only writable in Color Dreams mode. Translate to NINA-03 register arrangement */
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reg[0] =V <<3 &8 | V >>4 &7;
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Sync();
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}
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}
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static void Power(void) {
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reg[0] = 0;
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reg[1] = 0;
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Sync();
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SetWriteHandler(0x8000, 0xFFFF, WriteColorDreams);
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SetWriteHandler(0x4100, 0x7FFF, submapper == 1? WriteNINA_Prototype: WriteNINA08);
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SetReadHandler(0x8000, 0xFFFF, CartBR);
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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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static void Reset(void) {
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RAM[0x000] =0; /* Bug in Maxivision 30-in-1 1991-12-14 version */
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reg[0] = 0;
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reg[1] = 0;
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Sync();
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}
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void Mapper487_Init(CartInfo *info) {
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submapper = info->submapper;
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info->Power = Power;
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info->Reset = Reset;
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AddExState(&StateRegs, ~0, 0, 0);
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GameStateRestore = StateRestore;
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}
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