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c22eb807b0
No functions are changed. It just renames generic implementations from
'{func}_sse2' to '{func}_generic'. This is just because the postfix
"_sse2" was overloaded and was used for files that had hand-optimized
sse2 assembly implementations and files that just redirected back
to the generic implementation.
Full xcheck passed on x86_64.
137 lines
3.9 KiB
C
137 lines
3.9 KiB
C
/* strspn with SSE4.2 intrinsics
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Copyright (C) 2009-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <nmmintrin.h>
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#include <string.h>
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#include "varshift.h"
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/* We use 0x12:
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_SIDD_SBYTE_OPS
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| _SIDD_CMP_EQUAL_ANY
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| _SIDD_NEGATIVE_POLARITY
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| _SIDD_LEAST_SIGNIFICANT
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on pcmpistri to compare xmm/mem128
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0 1 2 3 4 5 6 7 8 9 A B C D E F
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X X X X X X X X X X X X X X X X
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against xmm
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0 1 2 3 4 5 6 7 8 9 A B C D E F
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A A A A A A A A A A A A A A A A
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to find out if the first 16byte data element has any non-A byte and
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the offset of the first byte. There are 2 cases:
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1. The first 16byte data element has the non-A byte, including
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EOS, at the offset X.
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2. The first 16byte data element is valid and doesn't have the non-A
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byte.
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Here is the table of ECX, CFlag, ZFlag and SFlag for 2 cases:
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case ECX CFlag ZFlag SFlag
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1 X 1 0/1 0
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2 16 0 0 0
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We exit from the loop for case 1. */
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extern size_t __strspn_generic (const char *, const char *) attribute_hidden;
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size_t
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__attribute__ ((section (".text.sse4.2")))
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__strspn_sse42 (const char *s, const char *a)
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{
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if (*a == 0)
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return 0;
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const char *aligned;
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__m128i mask, maskz, zero;
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unsigned int maskz_bits;
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unsigned int offset = (int) ((size_t) a & 15);
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zero = _mm_set1_epi8 (0);
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if (offset != 0)
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{
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/* Load masks. */
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aligned = (const char *) ((size_t) a & -16L);
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__m128i mask0 = _mm_load_si128 ((__m128i *) aligned);
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maskz = _mm_cmpeq_epi8 (mask0, zero);
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/* Find where the NULL terminator is. */
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maskz_bits = _mm_movemask_epi8 (maskz) >> offset;
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if (maskz_bits != 0)
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{
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mask = __m128i_shift_right (mask0, offset);
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offset = (unsigned int) ((size_t) s & 15);
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if (offset)
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goto start_unaligned;
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aligned = s;
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goto start_loop;
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}
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}
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/* A is aligned. */
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mask = _mm_loadu_si128 ((__m128i *) a);
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/* Find where the NULL terminator is. */
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maskz = _mm_cmpeq_epi8 (mask, zero);
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maskz_bits = _mm_movemask_epi8 (maskz);
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if (maskz_bits == 0)
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{
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/* There is no NULL terminator. Don't use SSE4.2 if the length
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of A > 16. */
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if (a[16] != 0)
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return __strspn_generic (s, a);
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}
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aligned = s;
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offset = (unsigned int) ((size_t) s & 15);
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if (offset != 0)
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{
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start_unaligned:
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/* Check partial string. */
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aligned = (const char *) ((size_t) s & -16L);
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__m128i value = _mm_load_si128 ((__m128i *) aligned);
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__m128i adj_value = __m128i_shift_right (value, offset);
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unsigned int length = _mm_cmpistri (mask, adj_value, 0x12);
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/* No need to check CFlag since it is always 1. */
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if (length < 16 - offset)
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return length;
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/* Find where the NULL terminator is. */
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maskz = _mm_cmpeq_epi8 (value, zero);
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maskz_bits = _mm_movemask_epi8 (maskz) >> offset;
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if (maskz_bits != 0)
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return length;
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aligned += 16;
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}
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start_loop:
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while (1)
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{
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__m128i value = _mm_load_si128 ((__m128i *) aligned);
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unsigned int index = _mm_cmpistri (mask, value, 0x12);
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unsigned int cflag = _mm_cmpistrc (mask, value, 0x12);
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if (cflag)
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return (size_t) (aligned + index - s);
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aligned += 16;
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}
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}
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