Files
ci-libretro-fceumm/src/boards/a9746.c

106 lines
2.6 KiB
C

/* FCE Ultra - NES/Famicom Emulator
*
* Copyright notice for this file:
* Copyright (C) 2007 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"
#include "mmc3.h"
static void UNLA9746PWrap(uint32 A, uint8 V) {
setprg8(A, EXPREGS[1] <<4 | V &0x0F);
}
static void UNLA9746CWrap(uint32 A, uint8 V) {
setchr1(A, EXPREGS[1] <<7 | V &0x7F);
}
static DECLFW(UNLA9746WriteOuter) {
switch(A &1) {
case 0: EXPREGS[1] =EXPREGS[1] &~1 | V >>3 &1; break;
case 1: EXPREGS[1] =EXPREGS[1] &~2 | V >>4 &2; break;
}
FixMMC3PRG(MMC3_cmd);
FixMMC3CHR(MMC3_cmd);
}
static DECLFW(UNLA9746WriteASIC) {
int index;
if (A &1)
{ /* Register data */
if (~EXPREGS[0] &0x20)
{ /* Scrambled mode inactive */
MMC3_CMDWrite(A, V);
}
else
{ /* Scrambled mode active */
if (MMC3_cmd >=0x08 && MMC3_cmd <=0x1F)
{ /* Scrambled CHR register */
index = (MMC3_cmd -8) >>2;
if (MMC3_cmd &1)
{ /* LSB nibble */
DRegBuf[index] &=~0x0F;
DRegBuf[index] |=V >>1 &0x0F;
}
else
{ /* MSB nibble */
DRegBuf[index] &=~0xF0;
DRegBuf[index] |=V <<4 &0xF0;
}
FixMMC3CHR(MMC3_cmd);
}
else
if (MMC3_cmd >=0x25 && MMC3_cmd <=0x26)
{ /* Scrambled PRG register */
DRegBuf[6 | MMC3_cmd &1] =V >>5 &1 | V >>3 &2 | V >>1 &4 | V <<1 &8;
FixMMC3PRG(MMC3_cmd);
}
}
}
else
{ /* Register index */
MMC3_CMDWrite(A, V);
if (A &2) EXPREGS[0] =V;
}
}
static void UNLA9746Power(void) {
GenMMC3Power();
SetWriteHandler(0x5000, 0x5FFF, UNLA9746WriteOuter);
SetWriteHandler(0x8000, 0xBFFF, UNLA9746WriteASIC);
EXPREGS[0] = 0;
EXPREGS[1] = 3;
MMC3RegReset();
}
static void UNLA9746Reset(void) {
EXPREGS[0] = 0;
EXPREGS[1] = 3;
MMC3RegReset();
}
void UNLA9746_Init(CartInfo *info) {
GenMMC3_Init(info, 128, 128, 0, 0);
pwrap = UNLA9746PWrap;
cwrap = UNLA9746CWrap;
info->Power = UNLA9746Power;
info->Reset = UNLA9746Reset;
AddExState(EXPREGS, 2, 0, "EXPR");
}