fceugx/source/fceultra/boards/8157.cpp
2012-12-14 17:43:51 +00:00

75 lines
1.9 KiB
C++

/* FCE Ultra - NES/Famicom Emulator
*
* Copyright notice for this file:
* Copyright (C) 2005 CaH4e3
*
* 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 uint16 cmdreg;
static uint8 invalid_data;
static SFORMAT StateRegs[] =
{
{ &invalid_data, 1, "INVD" },
{ &cmdreg, 2, "CREG" },
{ 0 }
};
static void Sync(void) {
setprg16r((cmdreg & 0x060) >> 5, 0x8000, (cmdreg & 0x01C) >> 2);
setprg16r((cmdreg & 0x060) >> 5, 0xC000, (cmdreg & 0x200) ? (~0) : 0);
setmirror(((cmdreg & 2) >> 1) ^ 1);
}
static DECLFR(UNL8157Read) {
if (invalid_data && cmdreg & 0x100)
return 0xFF;
else
return CartBR(A);
}
static DECLFW(UNL8157Write) {
cmdreg = A;
Sync();
}
static void UNL8157Power(void) {
setchr8(0);
SetWriteHandler(0x8000, 0xFFFF, UNL8157Write);
SetReadHandler(0x8000, 0xFFFF, UNL8157Read);
cmdreg = 0x200;
invalid_data = 1;
Sync();
}
static void UNL8157Reset(void) {
cmdreg = 0;
invalid_data ^= 1;
Sync();
}
static void UNL8157Restore(int version) {
Sync();
}
void UNL8157_Init(CartInfo *info) {
info->Power = UNL8157Power;
info->Reset = UNL8157Reset;
GameStateRestore = UNL8157Restore;
AddExState(&StateRegs, ~0, 0, 0);
}