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nRF51822/nordic/app_common/crc16.cpp@5:267bdacf5508, 2017-11-23 (annotated)
- Committer:
- tridung141196
- Date:
- Thu Nov 23 15:38:48 2017 +0000
- Revision:
- 5:267bdacf5508
- Parent:
- 0:76dfa9657d9d
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Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
jksoft | 0:76dfa9657d9d | 1 | /* Copyright (c) 2013 Nordic Semiconductor. All Rights Reserved. |
jksoft | 0:76dfa9657d9d | 2 | * |
jksoft | 0:76dfa9657d9d | 3 | * The information contained herein is property of Nordic Semiconductor ASA. |
jksoft | 0:76dfa9657d9d | 4 | * Terms and conditions of usage are described in detail in NORDIC |
jksoft | 0:76dfa9657d9d | 5 | * SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT. |
jksoft | 0:76dfa9657d9d | 6 | * |
jksoft | 0:76dfa9657d9d | 7 | * Licensees are granted free, non-transferable use of the information. NO |
jksoft | 0:76dfa9657d9d | 8 | * WARRANTY of ANY KIND is provided. This heading must NOT be removed from |
jksoft | 0:76dfa9657d9d | 9 | * the file. |
jksoft | 0:76dfa9657d9d | 10 | * |
jksoft | 0:76dfa9657d9d | 11 | */ |
jksoft | 0:76dfa9657d9d | 12 | |
jksoft | 0:76dfa9657d9d | 13 | #include "crc16.h" |
jksoft | 0:76dfa9657d9d | 14 | #include <stdio.h> |
jksoft | 0:76dfa9657d9d | 15 | |
jksoft | 0:76dfa9657d9d | 16 | uint16_t crc16_compute(const uint8_t * p_data, uint32_t size, const uint16_t * p_crc) |
jksoft | 0:76dfa9657d9d | 17 | { |
jksoft | 0:76dfa9657d9d | 18 | uint32_t i; |
jksoft | 0:76dfa9657d9d | 19 | uint16_t crc = (p_crc == NULL) ? 0xffff : *p_crc; |
jksoft | 0:76dfa9657d9d | 20 | |
jksoft | 0:76dfa9657d9d | 21 | for (i = 0; i < size; i++) |
jksoft | 0:76dfa9657d9d | 22 | { |
jksoft | 0:76dfa9657d9d | 23 | crc = (unsigned char)(crc >> 8) | (crc << 8); |
jksoft | 0:76dfa9657d9d | 24 | crc ^= p_data[i]; |
jksoft | 0:76dfa9657d9d | 25 | crc ^= (unsigned char)(crc & 0xff) >> 4; |
jksoft | 0:76dfa9657d9d | 26 | crc ^= (crc << 8) << 4; |
jksoft | 0:76dfa9657d9d | 27 | crc ^= ((crc & 0xff) << 4) << 1; |
jksoft | 0:76dfa9657d9d | 28 | } |
jksoft | 0:76dfa9657d9d | 29 | |
jksoft | 0:76dfa9657d9d | 30 | return crc; |
jksoft | 0:76dfa9657d9d | 31 | } |