tom dunigan / FastCRC

Port of teensy 3 FastCRC library, uses hardware CRC

Dependents:   fastCRCperf

Port of teensy 3 FastCRC library, uses hardware CRC on K64F. About 30 times faster than Arduino CRC (crc16.h).

https://github.com/FrankBoesing/FastCRC

teensy forum discussions on FastCRC https://forum.pjrc.com/threads/25699-Fast-CRC-library-(uses-the-built-in-crc-module-in-Teensy3)

crc16.h

Committer:
manitou
Date:
2016-04-22
Revision:
0:7343f324d853

File content as of revision 0:7343f324d853:

#ifndef _UTIL_CRC16_H_
#define _UTIL_CRC16_H_

#include <stdint.h>

static inline uint16_t _crc16_update(uint16_t crc, uint8_t data) __attribute__((always_inline, unused));
static inline uint16_t _crc16_update(uint16_t crc, uint8_t data)
{
    unsigned int i;

    crc ^= data;
    for (i = 0; i < 8; ++i) {
        if (crc & 1) {
            crc = (crc >> 1) ^ 0xA001;
        } else {
            crc = (crc >> 1);
        }
    }
    return crc;
}

static inline uint16_t _crc_xmodem_update(uint16_t crc, uint8_t data) __attribute__((always_inline, unused));
static inline uint16_t _crc_xmodem_update(uint16_t crc, uint8_t data)
{
    unsigned int i;

    crc = crc ^ ((uint16_t)data << 8);
    for (i=0; i<8; i++) {
        if (crc & 0x8000) {
            crc = (crc << 1) ^ 0x1021;
        } else {
            crc <<= 1;
        }
    }
    return crc;
}

static inline uint16_t _crc_ccitt_update (uint16_t crc, uint8_t data) __attribute__((always_inline, unused));
static inline uint16_t _crc_ccitt_update (uint16_t crc, uint8_t data)
{
    data ^= (crc & 255);
    data ^= data << 4;

    return ((((uint16_t)data << 8) | (crc >> 8)) ^ (uint8_t)(data >> 4) 
        ^ ((uint16_t)data << 3));
}

static inline uint8_t _crc_ibutton_update(uint8_t crc, uint8_t data) __attribute__((always_inline, unused));
static inline uint8_t _crc_ibutton_update(uint8_t crc, uint8_t data)
{
    unsigned int i;

    crc = crc ^ data;
    for (i = 0; i < 8; i++) {
        if (crc & 0x01) {
            crc = (crc >> 1) ^ 0x8C;
        } else {
            crc >>= 1;
        }
    }
    return crc;
}

#endif