forked from KolibriOS/kolibrios
132 lines
3.0 KiB
C
132 lines
3.0 KiB
C
|
/*
|
||
|
|
DGen/SDL v1.27+
|
||
|
|
|
||
|
|
Module for loading in the different ROM image types (.bin/.smd)
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <stdio.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <string.h>
|
||
|
|
#include <errno.h>
|
||
|
|
#include "romload.h"
|
||
|
|
#include "system.h"
|
||
|
|
|
||
|
|
static const char *rom_path = "roms";
|
||
|
|
|
||
|
|
void set_rom_path(const char *path)
|
||
|
|
{
|
||
|
|
rom_path = path;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
WHAT YOU FIND IN THE 512 BYTES HEADER:
|
||
|
|
|
||
|
|
0: Number of blocks 1
|
||
|
|
1: H03 *
|
||
|
|
2: SPLIT? 2
|
||
|
|
8: HAA *
|
||
|
|
9: HBB *
|
||
|
|
ALL OTHER BYTES: H00
|
||
|
|
|
||
|
|
1: This first byte should have the number of 16KB blocks the rom has.
|
||
|
|
The header isn't part of the formula, so this number is:
|
||
|
|
[size of rom-512]/16384
|
||
|
|
If the size is more than 255, the value should be H00.
|
||
|
|
|
||
|
|
2: This byte indicates if the ROM is a part of a splitted rom series. If
|
||
|
|
the rom is the last part of the series (or isn't a splitted rom at all),
|
||
|
|
this byte should be H00. In other cases should be H40. See "CREATING
|
||
|
|
SPLITTED ROMS" for details on this format.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/*
|
||
|
|
Allocate a buffer and stuff the named ROM inside. If rom_size is non-NULL,
|
||
|
|
store the ROM size there.
|
||
|
|
*/
|
||
|
|
|
||
|
|
uint8_t *load_rom(size_t *rom_size, const char *name)
|
||
|
|
{
|
||
|
|
FILE *file;
|
||
|
|
size_t size;
|
||
|
|
uint8_t *rom;
|
||
|
|
int error;
|
||
|
|
void *context = NULL;
|
||
|
|
|
||
|
|
if (name == NULL)
|
||
|
|
return NULL;
|
||
|
|
file = dgen_fopen(rom_path, name, (DGEN_READ | DGEN_CURRENT));
|
||
|
|
if (file == NULL) {
|
||
|
|
fprintf(stderr, "%s: can't open ROM file.\n", name);
|
||
|
|
return NULL;
|
||
|
|
}
|
||
|
|
retry:
|
||
|
|
/* A valid ROM will surely not be bigger than 64MB. */
|
||
|
|
rom = load(&context, &size, file, (64 * 1024 * 1024));
|
||
|
|
error = errno;
|
||
|
|
if (rom == NULL) {
|
||
|
|
if (error)
|
||
|
|
fprintf(stderr, "%s: unable to load ROM: %s.\n", name,
|
||
|
|
strerror(error));
|
||
|
|
else
|
||
|
|
fprintf(stderr, "%s: no valid ROM found.\n",
|
||
|
|
name);
|
||
|
|
load_finish(&context);
|
||
|
|
fclose(file);
|
||
|
|
return NULL;
|
||
|
|
}
|
||
|
|
if (size < 512) {
|
||
|
|
/* ROM file too small */
|
||
|
|
unload(rom);
|
||
|
|
goto retry;
|
||
|
|
}
|
||
|
|
/*
|
||
|
|
If "SEGA" isn't found at 0x100 and the total size minus 512 is a
|
||
|
|
multiple of 0x4000, it probably is a SMD.
|
||
|
|
*/
|
||
|
|
if (memcmp(&rom[0x100], "SEGA", 4)) {
|
||
|
|
uint8_t *dst = rom;
|
||
|
|
uint8_t *src = &rom[0x200];
|
||
|
|
size_t chunks = ((size - 0x200) / 0x4000);
|
||
|
|
|
||
|
|
if (((size - 0x200) & (0x4000 - 1)) != 0)
|
||
|
|
goto bad_rom;
|
||
|
|
size -= 0x200;
|
||
|
|
/* Corrupt ROM? Complain and continue anyway. */
|
||
|
|
if (((rom[0] != 0x00) && (rom[0] != chunks)) ||
|
||
|
|
(rom[8] != 0xaa) || (rom[9] != 0xbb))
|
||
|
|
fprintf(stderr, "%s: corrupt SMD header.\n", name);
|
||
|
|
/*
|
||
|
|
De-interleave ROM, overwrite SMD header with the result.
|
||
|
|
*/
|
||
|
|
while (chunks) {
|
||
|
|
size_t i;
|
||
|
|
uint8_t tmp[0x2000];
|
||
|
|
|
||
|
|
memcpy(tmp, src, 0x2000);
|
||
|
|
src += 0x2000;
|
||
|
|
for (i = 0; (i != 0x2000); ++i) {
|
||
|
|
*(dst++) = *(src++);
|
||
|
|
*(dst++) = tmp[i];
|
||
|
|
}
|
||
|
|
--chunks;
|
||
|
|
}
|
||
|
|
/* Does it look like a valid ROM now? */
|
||
|
|
if (memcmp(&rom[0x100], "SEGA", 4)) {
|
||
|
|
bad_rom:
|
||
|
|
/* Invalid ROM */
|
||
|
|
unload(rom);
|
||
|
|
goto retry;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
load_finish(&context);
|
||
|
|
fclose(file);
|
||
|
|
if (rom_size != NULL)
|
||
|
|
*rom_size = size;
|
||
|
|
return rom;
|
||
|
|
}
|
||
|
|
|
||
|
|
void unload_rom(uint8_t *rom)
|
||
|
|
{
|
||
|
|
unload(rom);
|
||
|
|
}
|