fceugx/source/fceultra/boards/67.cpp
2016-09-17 20:43:24 -07:00

107 lines
2.6 KiB
C++

/* FCE Ultra - NES/Famicom Emulator
*
* Copyright notice for this file:
* Copyright (C) 2012 CaH4e3
* Copyright (C) 2002 Xodnizel
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "mapinc.h"
static uint8 preg, creg[4], mirr, suntoggle = 0;
static uint8 IRQa;
static int16 IRQCount, IRQLatch;
static SFORMAT StateRegs[] =
{
{ &preg, 1, "PREG" },
{ &suntoggle, 1, "STOG" },
{ creg, 4, "CREG" },
{ &mirr, 1, "MIRR" },
{ &IRQa, 1, "IRQA" },
{ &IRQCount, 2, "IRQC" },
{ &IRQLatch, 2, "IRQL" },
{ 0 }
};
static void Sync(void) {
setmirror(mirr);
setprg16(0x8000, preg);
setprg16(0xC000, ~0);
setchr2(0x0000, creg[0]);
setchr2(0x0800, creg[1]);
setchr2(0x1000, creg[2]);
setchr2(0x1800, creg[3]);
switch (mirr) {
case 0: setmirror(MI_V); break;
case 1: setmirror(MI_H); break;
case 2: setmirror(MI_0); break;
case 3: setmirror(MI_1); break;
}
}
static DECLFW(M67Write) {
switch (A & 0xF800) {
case 0x8800: creg[0] = V; Sync(); break;
case 0x9800: creg[1] = V; Sync(); break;
case 0xA800: creg[2] = V; Sync(); break;
case 0xB800: creg[3] = V; Sync(); break;
case 0xC000:
case 0xC800:
IRQCount &= 0xFF << (suntoggle << 3);
IRQCount |= V << ((suntoggle ^ 1) << 3);
suntoggle ^= 1;
break;
case 0xD800:
suntoggle = 0;
IRQa = V & 0x10;
X6502_IRQEnd(FCEU_IQEXT);
break;
case 0xE800: mirr = V & 3; Sync(); break;
case 0xF800: preg = V; Sync(); break;
}
}
static void M67Power(void) {
suntoggle = 0;
Sync();
SetReadHandler(0x8000, 0xFFFF, CartBR);
SetWriteHandler(0x8000, 0xFFFF, M67Write);
}
void M67IRQ(int a) {
if (IRQa) {
IRQCount -= a;
if (IRQCount <= 0) {
X6502_IRQBegin(FCEU_IQEXT);
IRQa = 0;
IRQCount = -1;
}
}
}
static void StateRestore(int version) {
Sync();
}
void Mapper67_Init(CartInfo *info) {
info->Power = M67Power;
MapIRQHook = M67IRQ;
GameStateRestore = StateRestore;
AddExState(&StateRegs, ~0, 0, 0);
}