1 /*-------------------------------------------------------------------------
2 *
3 * pg_crc32c_armv8.c
4 * Compute CRC-32C checksum using ARMv8 CRC Extension 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_armv8.c
12 *
13 *-------------------------------------------------------------------------
14 */
15 #include "c.h"
16
17 #include <arm_acle.h>
18
19 #include "port/pg_crc32c.h"
20
21 pg_crc32c
pg_comp_crc32c_armv8(pg_crc32c crc,const void * data,size_t len)22 pg_comp_crc32c_armv8(pg_crc32c crc, const void *data, size_t len)
23 {
24 const unsigned char *p = data;
25 const unsigned char *pend = p + len;
26
27 /*
28 * ARMv8 doesn't require alignment, but aligned memory access is
29 * significantly faster. Process leading bytes so that the loop below
30 * starts with a pointer aligned to eight bytes.
31 */
32 if (!PointerIsAligned(p, uint16) &&
33 p + 1 <= pend)
34 {
35 crc = __crc32cb(crc, *p);
36 p += 1;
37 }
38 if (!PointerIsAligned(p, uint32) &&
39 p + 2 <= pend)
40 {
41 crc = __crc32ch(crc, *(uint16 *) p);
42 p += 2;
43 }
44 if (!PointerIsAligned(p, uint64) &&
45 p + 4 <= pend)
46 {
47 crc = __crc32cw(crc, *(uint32 *) p);
48 p += 4;
49 }
50
51 /* Process eight bytes at a time, as far as we can. */
52 while (p + 8 <= pend)
53 {
54 crc = __crc32cd(crc, *(uint64 *) p);
55 p += 8;
56 }
57
58 /* Process remaining 0-7 bytes. */
59 if (p + 4 <= pend)
60 {
61 crc = __crc32cw(crc, *(uint32 *) p);
62 p += 4;
63 }
64 if (p + 2 <= pend)
65 {
66 crc = __crc32ch(crc, *(uint16 *) p);
67 p += 2;
68 }
69 if (p < pend)
70 {
71 crc = __crc32cb(crc, *p);
72 }
73
74 return crc;
75 }
76