mirror of
https://github.com/dborth/fceugx.git
synced 2024-11-01 06:55:05 +01:00
136 lines
3.3 KiB
C++
136 lines
3.3 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) 2012 CaH4e3
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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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* VRC-3
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*
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*/
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#include "mapinc.h"
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static uint8 preg;
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static uint8 IRQx; //autoenable
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static uint8 IRQm; //mode
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static uint8 IRQa;
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static uint16 IRQReload, IRQCount;
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static uint8 *WRAM = NULL;
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static uint32 WRAMSIZE;
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static SFORMAT StateRegs[] =
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{
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{ &preg, 1, "PREG" },
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{ &IRQa, 1, "IRQA" },
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{ &IRQx, 1, "IRQX" },
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{ &IRQm, 1, "IRQM" },
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{ &IRQReload, 2, "IRQR" },
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{ &IRQCount, 2, "IRQC" },
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{ 0 }
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};
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static void Sync(void) {
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setprg8r(0x10, 0x6000, 0);
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setprg16(0x8000, preg);
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setprg16(0xC000, ~0);
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setchr8(0);
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}
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static DECLFW(M73Write) {
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switch (A & 0xF000) {
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case 0x8000: IRQReload &= 0xFFF0; IRQReload |= (V & 0xF) << 0; break;
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case 0x9000: IRQReload &= 0xFF0F; IRQReload |= (V & 0xF) << 4; break;
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case 0xA000: IRQReload &= 0xF0FF; IRQReload |= (V & 0xF) << 8; break;
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case 0xB000: IRQReload &= 0x0FFF; IRQReload |= (V & 0xF) << 12; break;
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case 0xC000:
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IRQm = V & 4;
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IRQx = V & 1;
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IRQa = V & 2;
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if (IRQa) {
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if (IRQm) {
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IRQCount &= 0xFFFF;
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IRQCount |= (IRQReload & 0xFF);
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} else
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IRQCount = IRQReload;
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}
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X6502_IRQEnd(FCEU_IQEXT);
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break;
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case 0xD000: X6502_IRQEnd(FCEU_IQEXT); IRQa = IRQx; break;
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case 0xF000: preg = V; Sync(); break;
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}
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}
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static void M73IRQHook(int a) {
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int32 i;
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if (!IRQa) return;
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for (i = 0; i < a; i++) {
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if (IRQm) {
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uint16 temp = IRQCount;
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temp &= 0xFF;
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IRQCount &= 0xFF00;
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if (temp == 0xFF) {
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IRQCount = IRQReload;
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IRQCount |= (uint16)(IRQReload & 0xFF);
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X6502_IRQBegin(FCEU_IQEXT);
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} else {
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temp++;
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IRQCount |= temp;
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}
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} else {
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//16 bit mode
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if (IRQCount == 0xFFFF) {
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IRQCount = IRQReload;
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X6502_IRQBegin(FCEU_IQEXT);
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} else
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IRQCount++;
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}
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}
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}
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static void M73Power(void) {
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IRQReload = IRQm = IRQx = 0;
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Sync();
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SetReadHandler(0x6000, 0xFFFF, CartBR);
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SetWriteHandler(0x6000, 0x7FFF, CartBW);
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SetWriteHandler(0x8000, 0xFFFF, M73Write);
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FCEU_CheatAddRAM(WRAMSIZE >> 10, 0x6000, WRAM);
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}
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static void M73Close(void)
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{
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if (WRAM)
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FCEU_gfree(WRAM);
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WRAM = NULL;
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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 Mapper73_Init(CartInfo *info) {
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info->Power = M73Power;
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info->Close = M73Close;
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MapIRQHook = M73IRQHook;
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WRAMSIZE = 8192;
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WRAM = (uint8*)FCEU_gmalloc(WRAMSIZE);
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SetupCartPRGMapping(0x10, WRAM, WRAMSIZE, 1);
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AddExState(WRAM, WRAMSIZE, 0, "WRAM");
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AddExState(&StateRegs, ~0, 0, 0);
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GameStateRestore = StateRestore;
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}
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