Line data    Source code

       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * pg_crc32c_sse42.c
       4             :  *    Compute CRC-32C checksum using Intel SSE 4.2 instructions.
       5             :  *
       6             :  * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
       7             :  * Portions Copyright (c) 1994, Regents of the University of California
       8             :  *
       9             :  *
      10             :  * IDENTIFICATION
      11             :  *    src/port/pg_crc32c_sse42.c
      12             :  *
      13             :  *-------------------------------------------------------------------------
      14             :  */
      15             : #include "c.h"
      16             : 
      17             : #include <nmmintrin.h>
      18             : 
      19             : #include "port/pg_crc32c.h"
      20             : 
      21             : pg_attribute_no_sanitize_alignment()
      22             : pg_attribute_target("sse4.2")
      23             : pg_crc32c
      24   156737904 : pg_comp_crc32c_sse42(pg_crc32c crc, const void *data, size_t len)
      25             : {
      26   156737904 :     const unsigned char *p = data;
      27   156737904 :     const unsigned char *pend = p + len;
      28             : 
      29             :     /*
      30             :      * Process eight bytes of data at a time.
      31             :      *
      32             :      * NB: We do unaligned accesses here. The Intel architecture allows that,
      33             :      * and performance testing didn't show any performance gain from aligning
      34             :      * the begin address.
      35             :      */
      36             : #ifdef __x86_64__
      37  7548847390 :     while (p + 8 <= pend)
      38             :     {
      39  7392109486 :         crc = (uint32) _mm_crc32_u64(crc, *((const uint64 *) p));
      40  7392109486 :         p += 8;
      41             :     }
      42             : 
      43             :     /* Process remaining full four bytes if any */
      44   156737904 :     if (p + 4 <= pend)
      45             :     {
      46    93787204 :         crc = _mm_crc32_u32(crc, *((const unsigned int *) p));
      47    93787204 :         p += 4;
      48             :     }
      49             : #else
      50             : 
      51             :     /*
      52             :      * Process four bytes at a time. (The eight byte instruction is not
      53             :      * available on the 32-bit x86 architecture).
      54             :      */
      55             :     while (p + 4 <= pend)
      56             :     {
      57             :         crc = _mm_crc32_u32(crc, *((const unsigned int *) p));
      58             :         p += 4;
      59             :     }
      60             : #endif                          /* __x86_64__ */
      61             : 
      62             :     /* Process any remaining bytes one at a time. */
      63   318086596 :     while (p < pend)
      64             :     {
      65   161348692 :         crc = _mm_crc32_u8(crc, *p);
      66   161348692 :         p++;
      67             :     }
      68             : 
      69   156737904 :     return crc;
      70             : }