claunia/86Box
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

CD-ROM: Parity and CRC checking support, System Shock 2 now works with a directly mounted .CUE image as well.

Browse Source
This commit is contained in:
OBattler
2025-07-24 14:12:20 +02:00
parent 362528de25
commit 8944c920ae
6 changed files with 10558 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

109
src/cdrom/cdrom.c
View File

@@ -292,10 +292,75 @@ msf_to_bcd(int *m, int *s, int *f)
*f = bin2bcd(*f);
}
static int
read_data(cdrom_t *dev, const uint32_t lba)
void
cdrom_compute_ecc_block(cdrom_t *dev, uint8_t *parity, const uint8_t *data,
uint32_t major_count, uint32_t minor_count,
uint32_t major_mult, uint32_t minor_inc)
{
int ret = 1;
uint32_t size = major_count * minor_count;
for (uint32_t major = 0; major < major_count; ++major) {
uint32_t index = (major >> 1) * major_mult + (major & 1);
uint8_t ecc_a = 0;
uint8_t ecc_b = 0;
for (uint32_t minor = 0; minor < minor_count; ++minor) {
uint8_t temp = data[index];
index += minor_inc;
if (index >= size)
index -= size;
ecc_a ^= temp;
ecc_b ^= temp;
ecc_a = dev->_F_LUT[ecc_a];
}
parity[major] = dev->_B_LUT[dev->_F_LUT[ecc_a] ^ ecc_b];
parity[major + major_count] = parity[major] ^ ecc_b;
}
}
extern void
cdrom_generate_ecc_data(cdrom_t *dev, const uint8_t *data)
{
/* Compute ECC P code. */
cdrom_compute_ecc_block(dev, dev->p_parity, data, 86, 24, 2, 86);
/* Compute ECC Q code. */
cdrom_compute_ecc_block(dev, dev->q_parity, data, 52, 43, 86, 88);
}
static int
cdrom_is_sector_good(cdrom_t *dev, const uint8_t *b, const uint8_t mode2, const uint8_t form)
{
int ret = 1;
if (mode2 && (form == 1)) {
const uint32_t crc = cdrom_crc32(0xffffffff, b, 2072) ^ 0xffffffff;
ret = ret && (crc == (*(uint32_t *) &(b[2072])));
} else if (!mode2) {
const uint32_t crc = cdrom_crc32(0xffffffff, b, 2064) ^ 0xffffffff;
ret = ret && (crc == (*(uint32_t *) &(b[2064])));
}
cdrom_generate_ecc_data(dev, &(b[12]));
ret = ret && !memcmp(dev->p_parity, &(b[2076]), 172);
ret = ret && !memcmp(dev->q_parity, &(b[2248]), 104);
return ret;
}
static int
read_data(cdrom_t *dev, const uint32_t lba, int check)
{
int ret = 1;
int form = 0;
if (dev->cached_sector != lba) {
dev->cached_sector = lba;
@@ -303,6 +368,25 @@ read_data(cdrom_t *dev, const uint32_t lba)
ret = dev->ops->read_sector(dev->local,
dev->raw_buffer[dev->cur_buf ^ 1], lba);
if ((ret > 0) && check) {
if (dev->mode2) {
if (dev->raw_buffer[dev->cur_buf ^ 1][0x000f] == 0x01)
/*
Use Mode 1, since evidently specification-violating
discs exist.
*/
dev->mode2 = 0;
else if (dev->raw_buffer[dev->cur_buf ^ 1][0x0012] ==
dev->raw_buffer[dev->cur_buf ^ 1][0x0016])
form = ((dev->raw_buffer[dev->cur_buf ^ 1][0x0012] &
0x20) >> 5) + 1;
} else if (dev->raw_buffer[dev->cur_buf ^ 1][0x000f] == 0x02)
dev->mode2 = 1;
if (!cdrom_is_sector_good(dev, dev->raw_buffer[dev->cur_buf ^ 1], dev->mode2, form))
ret = -1;
}
if (ret <= 0) {
memset(dev->raw_buffer[dev->cur_buf ^ 1], 0x00, 2448);
dev->cached_sector = -1;
@@ -322,7 +406,7 @@ cdrom_get_subchannel(cdrom_t *dev, const uint32_t lba,
if (lba != dev->cached_sector)
dev->cached_sector = -1;
(void) read_data(dev, lba);
(void) read_data(dev, lba, 0);
for (int i = 0; i < 12; i++)
for (int j = 0; j < 8; j++)
@@ -679,7 +763,7 @@ track_type_is_valid(UNUSED(const cdrom_t *dev), const int type, const int flags,
static int
read_audio(cdrom_t *dev, const uint32_t lba, uint8_t *b)
{
const int ret = read_data(dev, lba);
const int ret = read_data(dev, lba, 0);
memcpy(b, dev->raw_buffer[dev->cur_buf], 2352);
@@ -2379,6 +2463,8 @@ cdrom_readsector_raw(cdrom_t *dev, uint8_t *buffer, const int sector, const int
if (dm != CD_TRACK_NORMAL)
mode2 = 1;
dev->mode2 = mode2;
memset(dev->extra_buffer, 0, 296);
if ((cdrom_sector_flags & 0xf8) == 0x08) {
@@ -2405,7 +2491,7 @@ cdrom_readsector_raw(cdrom_t *dev, uint8_t *buffer, const int sector, const int
else
ret = read_audio(dev, lba, temp_b);
} else {
ret = read_data(dev, lba);
ret = read_data(dev, lba, 1);
/* Return with error if we had one. */
if (ret > 0) {
@@ -2800,7 +2886,7 @@ cdrom_read_track_information(cdrom_t *dev, const uint8_t *cdb, uint8_t *buffer)
}
if (track->adr_ctl & 0x04) {
ret = read_data(dev, start);
ret = read_data(dev, start, 0);
mode = dev->raw_buffer[dev->cur_buf][3];
}
} else if (track->point != 0xa2)
@@ -2829,9 +2915,9 @@ uint8_t
cdrom_get_current_mode(cdrom_t *dev)
{
if (dev->cached_sector == -1)
(void) read_data(dev, dev->seek_pos);
(void) read_data(dev, dev->seek_pos, 0);
else
(void) read_data(dev, dev->cached_sector);
(void) read_data(dev, dev->cached_sector, 0);
return dev->raw_buffer[dev->cur_buf][3];
}
@@ -3011,6 +3097,11 @@ cdrom_hard_reset(void)
cdrom_load(dev, dev->image_path, 0);
}
for (uint32_t j = 0; j < _LUT_SIZE; ++j) {
dev->_F_LUT[j] = (j << 1) ^ (j & 0x80 ? 0x11d : 0);
dev->_B_LUT[j ^ dev->_F_LUT[j]] = j;
}
}
}