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AP_Math: added crc_crc64()

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This commit is contained in:
Andrew Tridgell 2022-02-05 12:41:09 +11:00
parent 9fd14dbf94
commit e96507f55f
2 changed files with 28 additions and 0 deletions
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26
libraries/AP_Math/crc.cpp
View File

@ -468,3 +468,29 @@ uint16_t crc_crc16_ibm(uint16_t crc_accum, uint8_t *data_blk_ptr, uint16_t data_
return crc_accum;
}
/*
64 bit crc matching px4 bootloader
*/
uint64_t crc_crc64(const uint32_t *data, uint16_t num_words)
{
const uint64_t poly = 0x42F0E1EBA9EA3693ULL;
uint64_t crc = ~(0ULL);
while (num_words--) {
uint32_t value = *data++;
for (uint8_t j = 0; j < 4; j++) {
uint8_t byte = ((uint8_t *)&value)[j];
crc ^= (uint64_t)byte << 56u;
for (uint8_t i = 0; i < 8; i++) {
if (crc & (1ull << 63u)) {
crc = (uint64_t)(crc << 1u) ^ poly;
} else {
crc = (uint64_t)(crc << 1u);
}
}
}
}
crc ^= ~(0ULL);
return crc;
}

2
libraries/AP_Math/crc.h
View File

@ -48,3 +48,5 @@ uint16_t calc_crc_modbus(uint8_t *buf, uint16_t len);
#define FNV_1_OFFSET_BASIS_64 14695981039346656037UL
void hash_fnv_1a(uint32_t len, const uint8_t* buf, uint64_t* hash);
// CRC-64-WE using the polynomial of 0x42F0E1EBA9EA3693
uint64_t crc_crc64(const uint32_t *data, uint16_t num_words);