LCOV - code coverage report
Current view: top level - src/port - pg_crc32c_sse42.c (source / functions) Hit Total Coverage
Test: PostgreSQL 15devel Lines: 13 13 100.0 %
Date: 2021-12-04 22:09:09 Functions: 1 1 100.0 %
Legend: Lines: hit not hit

          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) 1996-2021, 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_crc32c
      23   138894694 : pg_comp_crc32c_sse42(pg_crc32c crc, const void *data, size_t len)
      24             : {
      25   138894694 :     const unsigned char *p = data;
      26   138894694 :     const unsigned char *pend = p + len;
      27             : 
      28             :     /*
      29             :      * Process eight bytes of data at a time.
      30             :      *
      31             :      * NB: We do unaligned accesses here. The Intel architecture allows that,
      32             :      * and performance testing didn't show any performance gain from aligning
      33             :      * the begin address.
      34             :      */
      35             : #ifdef __x86_64__
      36  1301554302 :     while (p + 8 <= pend)
      37             :     {
      38  1162659608 :         crc = (uint32) _mm_crc32_u64(crc, *((const uint64 *) p));
      39  1162659608 :         p += 8;
      40             :     }
      41             : 
      42             :     /* Process remaining full four bytes if any */
      43   138894694 :     if (p + 4 <= pend)
      44             :     {
      45    88783094 :         crc = _mm_crc32_u32(crc, *((const unsigned int *) p));
      46    88783094 :         p += 4;
      47             :     }
      48             : #else
      49             : 
      50             :     /*
      51             :      * Process four bytes at a time. (The eight byte instruction is not
      52             :      * available on the 32-bit x86 architecture).
      53             :      */
      54             :     while (p + 4 <= pend)
      55             :     {
      56             :         crc = _mm_crc32_u32(crc, *((const unsigned int *) p));
      57             :         p += 4;
      58             :     }
      59             : #endif                          /* __x86_64__ */
      60             : 
      61             :     /* Process any remaining bytes one at a time. */
      62   295646822 :     while (p < pend)
      63             :     {
      64   156752128 :         crc = _mm_crc32_u8(crc, *p);
      65   156752128 :         p++;
      66             :     }
      67             : 
      68   138894694 :     return crc;
      69             : }

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