68 lines
1.3 KiB
C
68 lines
1.3 KiB
C
enum { CRC_TABLE_SIZE = 0x100 };
|
|
|
|
static inline uint32_t
|
|
crc_reflect(uint32_t input)
|
|
{
|
|
uint32_t reflected = 0;
|
|
for (int i = 0; i < 4 * 8; i++) {
|
|
reflected <<= 1;
|
|
reflected |= input & 1;
|
|
input >>= 1;
|
|
}
|
|
return reflected;
|
|
}
|
|
|
|
static inline void
|
|
crc_be_fill_table(uint32_t *table, uint32_t polynomial)
|
|
{
|
|
const uint32_t lsb = 1 << 31;
|
|
uint32_t poly = polynomial;
|
|
|
|
for (int c = 0; c < CRC_TABLE_SIZE; c++, table++) {
|
|
uint32_t v = c << 24;
|
|
for (int i = 0; i < 8; i++) {
|
|
if (v & lsb) {
|
|
v <<= 1;
|
|
v ^= poly;
|
|
} else {
|
|
v <<= 1;
|
|
}
|
|
}
|
|
*table = v;
|
|
}
|
|
}
|
|
|
|
static inline void
|
|
crc_le_fill_table(uint32_t *table, uint32_t polynomial)
|
|
{
|
|
const uint32_t lsb = 1;
|
|
uint32_t poly = crc_reflect(polynomial);
|
|
|
|
for (int c = 0; c < CRC_TABLE_SIZE; c++, table++) {
|
|
uint32_t v = c;
|
|
for (int i = 0; i < 8; i++) {
|
|
if (v & lsb) {
|
|
v >>= 1;
|
|
v ^= poly;
|
|
} else {
|
|
v >>= 1;
|
|
}
|
|
}
|
|
*table = v;
|
|
}
|
|
}
|
|
|
|
static inline void
|
|
crc_be_cycle(uint32_t *table, uint32_t *remainder, uint8_t c)
|
|
{
|
|
const uint32_t byte = table[(((*remainder) >> 24) ^ c)];
|
|
*remainder = (((*remainder) << 8) ^ byte);
|
|
}
|
|
|
|
static inline void
|
|
crc_le_cycle(uint32_t *table, uint32_t *remainder, uint8_t c)
|
|
{
|
|
const uint32_t byte = table[((*remainder) ^ c) & 0xFF];
|
|
*remainder = ((*remainder) >> 8) ^ byte;
|
|
}
|