_mm_crc32_u64
Updated: March 2009
Microsoft Specific
Emits the Streaming SIMD Extensions 4 (SSE4) instruction crc32. This instruction adds one parameter to the CRC-32C checksum of the other parameter.
unsigned int64 _mm_crc32_u64 ( unsigned __int64 crc, unsigned __int64 v );
CRC32-C algorithm is based on polynomial 0x1EDC6F41. It is implemented by following little-endian convention. This means that the most significant bit is treated as the least significant bit in the quotient.
Before you use this intrinsic, software must ensure that the processor supports this instruction.
#include <stdio.h>
#include <nmmintrin.h>
int main ()
{
unsigned __int64 crc = 0x000011115555AAAA;
unsigned __int64 input = 0x88889999EEEE3333;
unsigned __int64 res = _mm_crc32_u64(crc, input);
printf_s("Result res: 0x%08X%08X\n", (unsigned int) (res>>32), res);
return 0;
}
Some mistakes in the text above
The polynomial is actually
0x11edc6f41 and not 0x1edc6f41, also even that the crc argument can be __int64, only lowest 32 bits are taken into account.
- 12/23/2009
- Vlad Krasnov
