76 lines
1.5 KiB
C
76 lines
1.5 KiB
C
/*-------------------------------------------------------------------------
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*
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* pg_crc32c_armv8.c
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* Compute CRC-32C checksum using ARMv8 CRC Extension instructions
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*
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* Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* src/port/pg_crc32c_armv8.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "c.h"
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#include <arm_acle.h>
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#include "port/pg_crc32c.h"
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pg_crc32c
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pg_comp_crc32c_armv8(pg_crc32c crc, const void *data, size_t len)
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{
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const unsigned char *p = data;
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const unsigned char *pend = p + len;
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/*
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* ARMv8 doesn't require alignment, but aligned memory access is
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* significantly faster. Process leading bytes so that the loop below
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* starts with a pointer aligned to eight bytes.
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*/
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if (!PointerIsAligned(p, uint16) &&
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p + 1 <= pend)
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{
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crc = __crc32cb(crc, *p);
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p += 1;
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}
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if (!PointerIsAligned(p, uint32) &&
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p + 2 <= pend)
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{
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crc = __crc32ch(crc, *(uint16 *) p);
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p += 2;
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}
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if (!PointerIsAligned(p, uint64) &&
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p + 4 <= pend)
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{
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crc = __crc32cw(crc, *(uint32 *) p);
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p += 4;
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}
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/* Process eight bytes at a time, as far as we can. */
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while (p + 8 <= pend)
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{
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crc = __crc32cd(crc, *(uint64 *) p);
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p += 8;
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}
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/* Process remaining 0-7 bytes. */
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if (p + 4 <= pend)
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{
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crc = __crc32cw(crc, *(uint32 *) p);
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p += 4;
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}
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if (p + 2 <= pend)
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{
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crc = __crc32ch(crc, *(uint16 *) p);
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p += 2;
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}
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if (p < pend)
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{
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crc = __crc32cb(crc, *p);
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}
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return crc;
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}
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