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Diffstat (limited to 'REORG.TODO/sysdeps/x86_64/multiarch/strcspn-c.c')
| -rw-r--r-- | REORG.TODO/sysdeps/x86_64/multiarch/strcspn-c.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/x86_64/multiarch/strcspn-c.c b/REORG.TODO/sysdeps/x86_64/multiarch/strcspn-c.c new file mode 100644 index 0000000000..67991b5ca7 --- /dev/null +++ b/REORG.TODO/sysdeps/x86_64/multiarch/strcspn-c.c @@ -0,0 +1,173 @@ +/* strcspn with SSE4.2 intrinsics + Copyright (C) 2009-2017 Free Software Foundation, Inc. + Contributed by Intel Corporation. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <nmmintrin.h> +#include <string.h> +#include "varshift.h" + +/* We use 0x2: + _SIDD_SBYTE_OPS + | _SIDD_CMP_EQUAL_ANY + | _SIDD_POSITIVE_POLARITY + | _SIDD_LEAST_SIGNIFICANT + on pcmpistri to compare xmm/mem128 + + 0 1 2 3 4 5 6 7 8 9 A B C D E F + X X X X X X X X X X X X X X X X + + against xmm + + 0 1 2 3 4 5 6 7 8 9 A B C D E F + A A A A A A A A A A A A A A A A + + to find out if the first 16byte data element has any byte A and + the offset of the first byte. There are 3 cases: + + 1. The first 16byte data element has the byte A at the offset X. + 2. The first 16byte data element has EOS and doesn't have the byte A. + 3. The first 16byte data element is valid and doesn't have the byte A. + + Here is the table of ECX, CFlag, ZFlag and SFlag for 2 cases: + + 1 X 1 0/1 0 + 2 16 0 1 0 + 3 16 0 0 0 + + We exit from the loop for cases 1 and 2 with jbe which branches + when either CFlag or ZFlag is 1. If CFlag == 1, ECX has the offset + X for case 1. */ + +#ifndef STRCSPN_SSE2 +# define STRCSPN_SSE2 __strcspn_sse2 +# define STRCSPN_SSE42 __strcspn_sse42 +#endif + +#ifdef USE_AS_STRPBRK +# define RETURN(val1, val2) return val1 +#else +# define RETURN(val1, val2) return val2 +#endif + +extern +#ifdef USE_AS_STRPBRK +char * +#else +size_t +#endif +STRCSPN_SSE2 (const char *, const char *); + + +#ifdef USE_AS_STRPBRK +char * +#else +size_t +#endif +__attribute__ ((section (".text.sse4.2"))) +STRCSPN_SSE42 (const char *s, const char *a) +{ + if (*a == 0) + RETURN (NULL, strlen (s)); + + const char *aligned; + __m128i mask; + int offset = (int) ((size_t) a & 15); + if (offset != 0) + { + /* Load masks. */ + aligned = (const char *) ((size_t) a & -16L); + __m128i mask0 = _mm_load_si128 ((__m128i *) aligned); + + mask = __m128i_shift_right (mask0, offset); + + /* Find where the NULL terminator is. */ + int length = _mm_cmpistri (mask, mask, 0x3a); + if (length == 16 - offset) + { + /* There is no NULL terminator. */ + __m128i mask1 = _mm_load_si128 ((__m128i *) (aligned + 16)); + int index = _mm_cmpistri (mask1, mask1, 0x3a); + length += index; + + /* Don't use SSE4.2 if the length of A > 16. */ + if (length > 16) + return STRCSPN_SSE2 (s, a); + + if (index != 0) + { + /* Combine mask0 and mask1. We could play games with + palignr, but frankly this data should be in L1 now + so do the merge via an unaligned load. */ + mask = _mm_loadu_si128 ((__m128i *) a); + } + } + } + else + { + /* A is aligned. */ + mask = _mm_load_si128 ((__m128i *) a); + + /* Find where the NULL terminator is. */ + int length = _mm_cmpistri (mask, mask, 0x3a); + if (length == 16) + { + /* There is no NULL terminator. Don't use SSE4.2 if the length + of A > 16. */ + if (a[16] != 0) + return STRCSPN_SSE2 (s, a); + } + } + + offset = (int) ((size_t) s & 15); + if (offset != 0) + { + /* Check partial string. */ + aligned = (const char *) ((size_t) s & -16L); + __m128i value = _mm_load_si128 ((__m128i *) aligned); + + value = __m128i_shift_right (value, offset); + + int length = _mm_cmpistri (mask, value, 0x2); + /* No need to check ZFlag since ZFlag is always 1. */ + int cflag = _mm_cmpistrc (mask, value, 0x2); + if (cflag) + RETURN ((char *) (s + length), length); + /* Find where the NULL terminator is. */ + int index = _mm_cmpistri (value, value, 0x3a); + if (index < 16 - offset) + RETURN (NULL, index); + aligned += 16; + } + else + aligned = s; + + while (1) + { + __m128i value = _mm_load_si128 ((__m128i *) aligned); + int index = _mm_cmpistri (mask, value, 0x2); + int cflag = _mm_cmpistrc (mask, value, 0x2); + int zflag = _mm_cmpistrz (mask, value, 0x2); + if (cflag) + RETURN ((char *) (aligned + index), (size_t) (aligned + index - s)); + if (zflag) + RETURN (NULL, + /* Find where the NULL terminator is. */ + (size_t) (aligned + _mm_cmpistri (value, value, 0x3a) - s)); + aligned += 16; + } +} |