mirror of
https://github.com/php/php-src.git
synced 2026-04-03 22:22:18 +02:00
90a5b871ef
This simplifies the code, and also might indirectly improve performance due to a decrease in instruction cache pressure. Although the latter is probably negligible. This works because 0x30 has no overlapping bits with [0, 9].
64 lines
2.1 KiB
C
64 lines
2.1 KiB
C
/*
|
|
+----------------------------------------------------------------------+
|
|
| Copyright (c) The PHP Group |
|
|
+----------------------------------------------------------------------+
|
|
| This source file is subject to version 3.01 of the PHP license, |
|
|
| that is bundled with this package in the file LICENSE, and is |
|
|
| available through the world-wide-web at the following url: |
|
|
| https://www.php.net/license/3_01.txt |
|
|
| If you did not receive a copy of the PHP license and are unable to |
|
|
| obtain it through the world-wide-web, please send a note to |
|
|
| license@php.net so we can mail you a copy immediately. |
|
|
+----------------------------------------------------------------------+
|
|
| Authors: Niels Dossche <nielsdos@php.net> |
|
|
+----------------------------------------------------------------------+
|
|
*/
|
|
|
|
#include "bcmath.h"
|
|
#include "convert.h"
|
|
#include "private.h"
|
|
#ifdef __SSE2__
|
|
# include <emmintrin.h>
|
|
#endif
|
|
|
|
char *bc_copy_and_toggle_bcd(char *restrict dest, const char *source, const char *source_end)
|
|
{
|
|
const size_t bulk_shift = SWAR_REPEAT('0');
|
|
|
|
#ifdef __SSE2__
|
|
/* SIMD SSE2 bulk shift + copy */
|
|
__m128i shift_vector = _mm_set1_epi8('0');
|
|
while (source + sizeof(__m128i) <= source_end) {
|
|
__m128i bytes = _mm_loadu_si128((const __m128i *) source);
|
|
bytes = _mm_xor_si128(bytes, shift_vector);
|
|
_mm_storeu_si128((__m128i *) dest, bytes);
|
|
|
|
source += sizeof(__m128i);
|
|
dest += sizeof(__m128i);
|
|
}
|
|
#endif
|
|
|
|
/* Handle sizeof(size_t) (i.e. 4/8) bytes at once.
|
|
* We know that adding/subtracting an individual byte cannot overflow,
|
|
* so it is possible to add/subtract an entire word of bytes at once
|
|
* by using SWAR_REPEAT. */
|
|
while (source + sizeof(size_t) <= source_end) {
|
|
size_t bytes;
|
|
memcpy(&bytes, source, sizeof(bytes));
|
|
|
|
bytes ^= bulk_shift;
|
|
memcpy(dest, &bytes, sizeof(bytes));
|
|
|
|
source += sizeof(size_t);
|
|
dest += sizeof(size_t);
|
|
}
|
|
|
|
while (source < source_end) {
|
|
*dest = *source ^ '0';
|
|
dest++;
|
|
source++;
|
|
}
|
|
|
|
return dest;
|
|
}
|