diff options
Diffstat (limited to 'lib/crc8.c')
| -rw-r--r-- | lib/crc8.c | 33 |
1 files changed, 20 insertions, 13 deletions
diff --git a/lib/crc8.c b/lib/crc8.c index 8b68a29e40..51d540fbcb 100644 --- a/lib/crc8.c +++ b/lib/crc8.c @@ -6,20 +6,27 @@ #include "linux/crc8.h" -unsigned int crc8(const unsigned char *vptr, int len) +#define POLY (0x1070U << 3) + +static unsigned char _crc8(unsigned short data) { - const unsigned char *data = vptr; - unsigned int crc = 0; - int i, j; - - for (j = len; j; j--, data++) { - crc ^= (*data << 8); - for (i = 8; i; i--) { - if (crc & 0x8000) - crc ^= (0x1070 << 3); - crc <<= 1; - } + int i; + + for (i = 0; i < 8; i++) { + if (data & 0x8000) + data = data ^ POLY; + data = data << 1; } - return (crc >> 8) & 0xff; + return (unsigned char)(data >> 8); +} + +unsigned int crc8(unsigned int crc, const unsigned char *vptr, int len) +{ + int i; + + for (i = 0; i < len; i++) + crc = _crc8((crc ^ vptr[i]) << 8); + + return crc; } |