/*------------------------------------------------------------------------- * * pg_crc32c_armv8.c * Compute CRC-32C checksum using ARMv8 CRC Extension instructions * * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * src/port/pg_crc32c_armv8.c * *------------------------------------------------------------------------- */ #include "c.h" #include <arm_acle.h> #include "port/pg_crc32c.h" pg_crc32c pg_comp_crc32c_armv8(pg_crc32c crc, const void *data, size_t len) { const unsigned char *p = data; const unsigned char *pend = p + len; /* * ARMv8 doesn't require alignment, but aligned memory access is * significantly faster. Process leading bytes so that the loop below * starts with a pointer aligned to eight bytes. */ if (!PointerIsAligned(p, uint16) && p + 1 <= pend) { crc = __crc32cb(crc, *p); p += 1; } if (!PointerIsAligned(p, uint32) && p + 2 <= pend) { crc = __crc32ch(crc, *(uint16 *) p); p += 2; } if (!PointerIsAligned(p, uint64) && p + 4 <= pend) { crc = __crc32cw(crc, *(uint32 *) p); p += 4; } /* Process eight bytes at a time, as far as we can. */ while (p + 8 <= pend) { crc = __crc32cd(crc, *(uint64 *) p); p += 8; } /* Process remaining 0-7 bytes. */ if (p + 4 <= pend) { crc = __crc32cw(crc, *(uint32 *) p); p += 4; } if (p + 2 <= pend) { crc = __crc32ch(crc, *(uint16 *) p); p += 2; } if (p < pend) { crc = __crc32cb(crc, *p); } return crc; }