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/*
* Copyright 2010-2016, Tarantool AUTHORS, please see AUTHORS file.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* 1. Redistributions of source code must retain the above
* copyright notice, this list of conditions and the
* following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY <COPYRIGHT HOLDER> ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* <COPYRIGHT HOLDER> OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
* THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "trivia/config.h"
#include "trivia/util.h"
#include <sys/types.h>
#include <errno.h>
#include <stdlib.h>
#include <stdbool.h>
#include "cpu_feature.h"
#if defined(HAVE_CPUID) && (defined (__x86_64__) || defined (__i386__))
#include <cpuid.h>
#define SCALE_F sizeof(unsigned long)
#if defined (__x86_64__)
#define REX_PRE "0x48, "
#elif defined (__i386__)
#define REX_PRE
#endif
static uint32_t
crc32c_hw_byte(uint32_t crc, char const *data, unsigned int length)
{
while (length--) {
__asm__ __volatile__(
".byte 0xf2, 0xf, 0x38, 0xf0, 0xf1"
:"=S"(crc)
:"0"(crc), "c"(*data)
);
data++;
}
return crc;
}
uint32_t
crc32c_hw(uint32_t crc, const char *buf, unsigned int len)
{
const unsigned int align = alignof(unsigned long);
unsigned int not_aligned_prefix =
(align - (unsigned long)buf % align) % align;
/*
* Calculate CRC32 for the prefix byte-by-byte so as to
* then use aligned words to calculate the rest. This is
* twice less loads, because every load takes exactly one
* word from memory. Not 2 words, which would need to be
* partially merged then.
* But the main reason is that unaligned loads are just
* unsafe, because this is an undefined behaviour.
*/
if (not_aligned_prefix < len) {
crc = crc32c_hw_byte(crc, buf, not_aligned_prefix);
buf += not_aligned_prefix;
len -= not_aligned_prefix;
} else {
return crc32c_hw_byte(crc, buf, len);
}
unsigned int iquotient = len / SCALE_F;
unsigned int iremainder = len % SCALE_F;
unsigned long *ptmp = (unsigned long *)buf;
while (iquotient--) {
__asm__ __volatile__(
".byte 0xf2, " REX_PRE "0xf, 0x38, 0xf1, 0xf1;"
:"=S"(crc)
:"0"(crc), "c"(*ptmp)
);
ptmp++;
}
return crc32c_hw_byte(crc, (const char *)ptmp, iremainder);
}
bool
sse42_enabled_cpu()
{
unsigned int ax, bx, cx, dx;
if (__get_cpuid(1, &ax, &bx, &cx, &dx) == 0)
return 0;
return (cx & (1 << 20)) != 0;
}
#else /* !(defined (__x86_64__) || defined (__i386__)) */
bool
sse42_enabled_cpu()
{
return false;
}
#endif
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