From 46651ce6fe013220ed397add242004d764fc0153 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 4 May 2024 14:15:05 +0200 Subject: Adding upstream version 14.5. Signed-off-by: Daniel Baumann --- src/port/pg_crc32c_sse42_choose.c | 64 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) create mode 100644 src/port/pg_crc32c_sse42_choose.c (limited to 'src/port/pg_crc32c_sse42_choose.c') diff --git a/src/port/pg_crc32c_sse42_choose.c b/src/port/pg_crc32c_sse42_choose.c new file mode 100644 index 0000000..0608e02 --- /dev/null +++ b/src/port/pg_crc32c_sse42_choose.c @@ -0,0 +1,64 @@ +/*------------------------------------------------------------------------- + * + * pg_crc32c_sse42_choose.c + * Choose between Intel SSE 4.2 and software CRC-32C implementation. + * + * On first call, checks if the CPU we're running on supports Intel SSE + * 4.2. If it does, use the special SSE instructions for CRC-32C + * computation. Otherwise, fall back to the pure software implementation + * (slicing-by-8). + * + * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * + * IDENTIFICATION + * src/port/pg_crc32c_sse42_choose.c + * + *------------------------------------------------------------------------- + */ + +#include "c.h" + +#ifdef HAVE__GET_CPUID +#include +#endif + +#ifdef HAVE__CPUID +#include +#endif + +#include "port/pg_crc32c.h" + +static bool +pg_crc32c_sse42_available(void) +{ + unsigned int exx[4] = {0, 0, 0, 0}; + +#if defined(HAVE__GET_CPUID) + __get_cpuid(1, &exx[0], &exx[1], &exx[2], &exx[3]); +#elif defined(HAVE__CPUID) + __cpuid(exx, 1); +#else +#error cpuid instruction not available +#endif + + return (exx[2] & (1 << 20)) != 0; /* SSE 4.2 */ +} + +/* + * This gets called on the first call. It replaces the function pointer + * so that subsequent calls are routed directly to the chosen implementation. + */ +static pg_crc32c +pg_comp_crc32c_choose(pg_crc32c crc, const void *data, size_t len) +{ + if (pg_crc32c_sse42_available()) + pg_comp_crc32c = pg_comp_crc32c_sse42; + else + pg_comp_crc32c = pg_comp_crc32c_sb8; + + return pg_comp_crc32c(crc, data, len); +} + +pg_crc32c (*pg_comp_crc32c) (pg_crc32c crc, const void *data, size_t len) = pg_comp_crc32c_choose; -- cgit v1.2.3