Files
ci-libretro-fceumm/src/boards/cheapocabra.c
2022-02-12 16:13:05 +08:00

269 lines
6.6 KiB
C

/* FCE Ultra - NES/Famicom Emulator
*
* Copyright notice for this file:
* 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
*/
/* mapper 111 - Cheapocabra board by Memblers
* http://forums.nesdev.com/viewtopic.php?p=146039
*
* 512k PRG-ROM in 32k pages (flashable if battery backed is specified)
* 32k CHR-RAM used as:
* 2 x 8k pattern pages
* 2 x 8k nametable pages
*
* Notes:
* - CHR-RAM for nametables maps to $3000-3FFF as well, but FCEUX internally mirrors to 4k?
*/
#include "mapinc.h"
static uint8 reg;
static uint8 *CHRRAM = NULL;
static uint32 CHRRAMSIZE;
static uint8 flash = 0;
static uint8 flash_mode;
static uint8 flash_sequence;
static uint8 flash_id;
static uint8 *FLASHROM = NULL;
static uint32 FLASHROMSIZE;
static SFORMAT StateRegs[] = {
{ &reg, 1, "REG" },
{ 0 }
};
static SFORMAT FlashRegs[] = {
{ &flash_mode, 1, "FMOD" },
{ &flash_sequence, 1, "FSEQ" },
{ &flash_id, 1, "FMID" },
{ 0 }
};
static void Sync(void) {
/* bit 7 controls green LED */
/* bit 6 controls red LED */
uint32 prg_chip = flash ? 0x10 : 0;
int nt = (reg & 0x20) ? 8192 : 0; /* bit 5 controls 8k nametable page */
int chr = (reg & 0x10) ? 1 : 0; /* bit 4 selects 8k CHR page */
int prg = (reg & 0x0F); /* bits 0-3 select 32k PRG page */
int n = 0;
nt += (16 * 1024);
for (n = 0; n < 4; ++n) {
setntamem(CHRRAM + nt + (1024 * n), 1, n);
}
setchr8r(0x10, chr);
setprg32r(prg_chip, 0x8000, prg);
}
static DECLFW(M111Write) {
if ((A >= 0x5000 && A <= 0x5FFF) || (A >= 0x7000 && A <= 0x7FFF)) {
reg = V;
Sync();
}
}
static DECLFR(M111FlashID) {
/* Software ID mode is undefined by the datasheet for all but the lowest 2 addressable bytes,
* but some tests of the chip currently being used found it repeats in 512-byte patterns.
* http://forums.nesdev.com/viewtopic.php?p=178728#p178728
*/
uint32 aid = A & 0x1FF;
switch (aid) {
case 0:
return 0xBF;
case 1:
return 0xB7;
default:
return 0xFF;
}
}
void M111FlashIDEnter() {
if (flash_id)
return;
flash_id = 1;
SetReadHandler(0x8000, 0xFFFF, M111FlashID);
}
void M111FlashIDExit() {
if (!flash_id)
return;
flash_id = 0;
SetReadHandler(0x8000, 0xFFFF, CartBR);
}
enum {
FLASH_MODE_READY = 0,
FLASH_MODE_COMMAND,
FLASH_MODE_BYTE_WRITE,
FLASH_MODE_ERASE,
};
static DECLFW(M111Flash) {
uint32 flash_addr = 0;
uint32 command_addr = 0;
if (A < 0x8000 || A > 0xFFFF)
return;
flash_addr = ((reg & 0x0F) << 15) | (A & 0x7FFF);
command_addr = flash_addr & 0x7FFF;
switch (flash_mode) {
default:
case FLASH_MODE_READY:
if (command_addr == 0x5555 && V == 0xAA) {
flash_mode = FLASH_MODE_COMMAND;
flash_sequence = 0;
} else if (V == 0xF0) {
M111FlashIDExit();
}
break;
case FLASH_MODE_COMMAND:
if (flash_sequence == 0) {
if (command_addr == 0x2AAA && V == 0x55)
flash_sequence = 1;
else
flash_mode = FLASH_MODE_READY;
} else if (flash_sequence == 1) {
if (command_addr == 0x5555) {
flash_sequence = 0;
switch (V) {
default:
flash_mode = FLASH_MODE_READY;
break;
case 0xA0:
flash_mode = FLASH_MODE_BYTE_WRITE;
break;
case 0x80:
flash_mode = FLASH_MODE_ERASE;
break;
case 0x90:
M111FlashIDEnter();
flash_mode = FLASH_MODE_READY;
break;
case 0xF0:
M111FlashIDExit();
flash_mode = FLASH_MODE_READY;
break;
}
} else
flash_mode = FLASH_MODE_READY;
} else
flash_mode = FLASH_MODE_READY; /* should be unreachable */
break;
case FLASH_MODE_BYTE_WRITE:
FLASHROM[flash_addr] &= V;
flash_mode = FLASH_MODE_READY;
break;
case FLASH_MODE_ERASE:
if (flash_sequence == 0) {
if (command_addr == 0x5555 && V == 0xAA)
flash_sequence = 1;
else
flash_mode = FLASH_MODE_READY;
} else if (flash_sequence == 1) {
if (command_addr == 0x2AAA && V == 0x55)
flash_sequence = 2;
else
flash_mode = FLASH_MODE_READY;
} else if (flash_sequence == 2) {
if (command_addr == 0x5555 && V == 0x10) /* erase chip */
{
memset(FLASHROM, 0xFF, FLASHROMSIZE);
} else if (V == 0x30) /* erase 4k sector */
{
uint32 sector = flash_addr & 0x7F000;
memset(FLASHROM + sector, 0xFF, 1024 * 4);
}
flash_mode = FLASH_MODE_READY;
} else
flash_mode = FLASH_MODE_READY; /* should be unreachable */
break;
}
}
static void M111Power(void) {
reg = 0xFF;
Sync();
SetReadHandler(0x8000, 0xffff, CartBR);
SetWriteHandler(0x5000, 0x5fff, M111Write);
SetWriteHandler(0x7000, 0x7fff, M111Write);
if (flash) {
flash_mode = 0;
flash_sequence = 0;
flash_id = 0;
SetWriteHandler(0x8000, 0xFFFF, M111Flash);
}
}
static void M111Close(void) {
if (CHRRAM)
FCEU_gfree(CHRRAM);
CHRRAM = NULL;
if (FLASHROM)
FCEU_gfree(FLASHROM);
FLASHROM = NULL;
}
static void StateRestore(int version) {
Sync();
}
void Mapper111_Init(CartInfo* info) {
info->Power = M111Power;
info->Close = M111Close;
CHRRAMSIZE = 1024 * 32;
CHRRAM = (uint8*)FCEU_gmalloc(CHRRAMSIZE);
SetupCartCHRMapping(0x10, CHRRAM, CHRRAMSIZE, 1);
GameStateRestore = StateRestore;
AddExState(&StateRegs, ~0, 0, 0);
AddExState(CHRRAM, CHRRAMSIZE, 0, "CRAM");
flash = (info->battery != 0);
if (flash) {
uint32 PRGSIZE = 0;
uint32 w = 0;
uint32 r = 0;
FLASHROMSIZE = 1024 * 512;
FLASHROM = (uint8*)FCEU_gmalloc(FLASHROMSIZE);
info->SaveGame[0] = FLASHROM;
info->SaveGameLen[0] = FLASHROMSIZE;
AddExState(FLASHROM, FLASHROMSIZE, 0, "FROM");
AddExState(&FlashRegs, ~0, 0, 0);
/* copy PRG ROM into FLASHROM, use it instead of PRG ROM */
PRGSIZE = ROM_size * 16 * 1024;
for (w = 0, r = 0; w < FLASHROMSIZE; ++w) {
FLASHROM[w] = ROM[r];
++r;
if (r >= PRGSIZE)
r = 0;
}
SetupCartPRGMapping(0x10, FLASHROM, FLASHROMSIZE, 0);
}
}