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/*-
* Public Domain 2014-2016 MongoDB, Inc.
* Public Domain 2008-2014 WiredTiger, Inc.
*
* This is free and unencumbered software released into the public domain.
*
* Anyone is free to copy, modify, publish, use, compile, sell, or
* distribute this software, either in source code form or as a compiled
* binary, for any purpose, commercial or non-commercial, and by any
* means.
*
* In jurisdictions that recognize copyright laws, the author or authors
* of this software dedicate any and all copyright interest in the
* software to the public domain. We make this dedication for the benefit
* of the public at large and to the detriment of our heirs and
* successors. We intend this dedication to be an overt act of
* relinquishment in perpetuity of all present and future rights to this
* software under copyright law.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#include "wt_internal.h"
#if defined(HAVE_CRC32_HARDWARE)
#if (defined(__amd64) || defined(__x86_64))
/*
* __wt_checksum_hw --
* Return a checksum for a chunk of memory, computed in hardware
* using 8 byte steps.
*/
static uint32_t
__wt_checksum_hw(const void *chunk, size_t len)
{
uint32_t crc;
size_t nqwords;
const uint8_t *p;
const uint64_t *p64;
crc = 0xffffffff;
/* Checksum one byte at a time to the first 4B boundary. */
for (p = chunk;
((uintptr_t)p & (sizeof(uint32_t) - 1)) != 0 &&
len > 0; ++p, --len) {
__asm__ __volatile__(
".byte 0xF2, 0x0F, 0x38, 0xF0, 0xF1"
: "=S" (crc)
: "0" (crc), "c" (*p));
}
p64 = (const uint64_t *)p;
/* Checksum in 8B chunks. */
for (nqwords = len / sizeof(uint64_t); nqwords; nqwords--) {
__asm__ __volatile__ (
".byte 0xF2, 0x48, 0x0F, 0x38, 0xF1, 0xF1"
: "=S"(crc)
: "0"(crc), "c" (*p64));
p64++;
}
/* Checksum trailing bytes one byte at a time. */
p = (const uint8_t *)p64;
for (len &= 0x7; len > 0; ++p, len--) {
__asm__ __volatile__(
".byte 0xF2, 0x0F, 0x38, 0xF0, 0xF1"
: "=S" (crc)
: "0" (crc), "c" (*p));
}
return (~crc);
}
#endif
#if defined(_M_AMD64)
/*
* __wt_checksum_hw --
* Return a checksum for a chunk of memory, computed in hardware
* using 8 byte steps.
*/
static uint32_t
__wt_checksum_hw(const void *chunk, size_t len)
{
uint32_t crc;
size_t nqwords;
const uint8_t *p;
const uint64_t *p64;
crc = 0xffffffff;
/* Checksum one byte at a time to the first 4B boundary. */
for (p = chunk;
((uintptr_t)p & (sizeof(uint32_t) - 1)) != 0 &&
len > 0; ++p, --len) {
crc = _mm_crc32_u8(crc, *p);
}
p64 = (const uint64_t *)p;
/* Checksum in 8B chunks. */
for (nqwords = len / sizeof(uint64_t); nqwords; nqwords--) {
crc = (uint32_t)_mm_crc32_u64(crc, *p64);
p64++;
}
/* Checksum trailing bytes one byte at a time. */
p = (const uint8_t *)p64;
for (len &= 0x7; len > 0; ++p, len--) {
crc = _mm_crc32_u8(crc, *p);
}
return (~crc);
}
#endif
#endif /* HAVE_CRC32_HARDWARE */
/*
* __wt_checksum_init --
* WiredTiger: detect CRC hardware and set the checksum function.
*/
void
__wt_checksum_init(void)
{
#if defined(HAVE_CRC32_HARDWARE)
#if (defined(__amd64) || defined(__x86_64))
unsigned int eax, ebx, ecx, edx;
__asm__ __volatile__ (
"cpuid"
: "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx)
: "a" (1));
#define CPUID_ECX_HAS_SSE42 (1 << 20)
if (ecx & CPUID_ECX_HAS_SSE42)
__wt_process.checksum = __wt_checksum_hw;
else
__wt_process.checksum = __wt_checksum_sw;
#elif defined(_M_AMD64)
int cpuInfo[4];
__cpuid(cpuInfo, 1);
#define CPUID_ECX_HAS_SSE42 (1 << 20)
if (cpuInfo[2] & CPUID_ECX_HAS_SSE42)
__wt_process.checksum = __wt_checksum_hw;
else
__wt_process.checksum = __wt_checksum_sw;
#else
__wt_process.checksum = __wt_checksum_sw;
#endif
#else /* !HAVE_CRC32_HARDWARE */
__wt_process.checksum = __wt_checksum_sw;
#endif /* HAVE_CRC32_HARDWARE */
}
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