src/port/pg_crc32c_loongarch.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * pg_crc32c_loongarch.c
   4  *        Compute CRC-32C checksum using LoongArch CRCC instructions
   5  *
   6  * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        src/port/pg_crc32c_loongarch.c
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15 #include "c.h"
  16
  17 #include "port/pg_crc32c.h"
  18
  19 pg_crc32c
  20 pg_comp_crc32c_loongarch(pg_crc32c crc, const void *data, size_t len)
  21 {
  22         const unsigned char *p = data;
  23         const unsigned char *pend = p + len;
  24
  25         /*
  26          * LoongArch doesn't require alignment, but aligned memory access is
  27          * significantly faster. Process leading bytes so that the loop below
  28          * starts with a pointer aligned to eight bytes.
  29          */
  30         if (!PointerIsAligned(p, uint16) &&
  31                 p + 1 <= pend)
  32         {
  33                 crc = __builtin_loongarch_crcc_w_b_w(*p, crc);
  34                 p += 1;
  35         }
  36         if (!PointerIsAligned(p, uint32) &&
  37                 p + 2 <= pend)
  38         {
  39                 crc = __builtin_loongarch_crcc_w_h_w(*(uint16 *) p, crc);
  40                 p += 2;
  41         }
  42         if (!PointerIsAligned(p, uint64) &&
  43                 p + 4 <= pend)
  44         {
  45                 crc = __builtin_loongarch_crcc_w_w_w(*(uint32 *) p, crc);
  46                 p += 4;
  47         }
  48
  49         /* Process eight bytes at a time, as far as we can. */
  50         while (p + 8 <= pend)
  51         {
  52                 crc = __builtin_loongarch_crcc_w_d_w(*(uint64 *) p, crc);
  53                 p += 8;
  54         }
  55
  56         /* Process remaining 0-7 bytes. */
  57         if (p + 4 <= pend)
  58         {
  59                 crc = __builtin_loongarch_crcc_w_w_w(*(uint32 *) p, crc);
  60                 p += 4;
  61         }
  62         if (p + 2 <= pend)
  63         {
  64                 crc = __builtin_loongarch_crcc_w_h_w(*(uint16 *) p, crc);
  65                 p += 2;
  66         }
  67         if (p < pend)
  68         {
  69                 crc = __builtin_loongarch_crcc_w_b_w(*p, crc);
  70         }
  71
  72         return crc;
  73 }