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Diffstat (limited to 'sysdeps/tile/tilegx/strstr.c')
| -rw-r--r-- | sysdeps/tile/tilegx/strstr.c | 271 |
1 files changed, 271 insertions, 0 deletions
diff --git a/sysdeps/tile/tilegx/strstr.c b/sysdeps/tile/tilegx/strstr.c new file mode 100644 index 0000000000..2627e758c7 --- /dev/null +++ b/sysdeps/tile/tilegx/strstr.c @@ -0,0 +1,271 @@ +/* strstr with Tile intrinsics + Copyright (C) 2013 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, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +/* Specification of strstr. */ +#include <string.h> + +#include <stdbool.h> +#include "string-endian.h" + +#define RETURN_TYPE char * +#define AVAILABLE(h, h_l, j, n_l) \ + (!memchr ((h) + (h_l), '\0', (j) + (n_l) - (h_l)) \ + && ((h_l) = (j) + (n_l))) +#include "str-two-way.h" + +#undef strstr + +#ifndef STRSTR +#define STRSTR strstr +#endif + +#ifndef STRSTR2 +#define STRSTR2 strstr2 +#endif + +#ifndef STRCHR +#define STRCHR strchr +#endif + +#ifndef STRSTR_SCAN +#define STRSTR_SCAN strstr_scan +#endif + +#ifndef TOLOWER +# define TOLOWER(Ch) (Ch) +#endif + +#ifdef USE_AS_STRCASESTR + +static uint64_t +vec_tolower (uint64_t cc) +{ + /* For Uppercases letters, add 32 to convert to lower case. */ + uint64_t less_than_eq_Z = __insn_v1cmpltui (cc, 'Z' + 1); + uint64_t less_than_A = __insn_v1cmpltui (cc, 'A'); + uint64_t is_upper = __insn_v1cmpne (less_than_eq_Z, less_than_A); + return __insn_v1add (cc,__insn_v1shli (is_upper, 5)); +} + +/* There is no strcasechr() defined, but needed for 1 byte case + of strcasestr(), so create it here. */ + +static char * +strcasechr (const char *s, int c) +{ + int z, g; + + c = tolower (c); + + /* Get an aligned pointer. */ + const uintptr_t s_int = (uintptr_t) s; + const uint64_t *p = (const uint64_t *) (s_int & -8); + + /* Create eight copies of the byte for which we are looking. */ + const uint64_t goal = copy_byte(c); + + /* Read the first aligned word, but force bytes before the string to + match neither zero nor goal (we make sure the high bit of each byte + is 1, and the low 7 bits are all the opposite of the goal byte). */ + const uint64_t before_mask = MASK (s_int); + uint64_t v = + (vec_tolower (*p) | before_mask) ^ (goal & __insn_v1shrui (before_mask, 1)); + + uint64_t zero_matches, goal_matches; + while (1) + { + /* Look for a terminating '\0'. */ + zero_matches = __insn_v1cmpeqi (v, 0); + + /* Look for the goal byte. */ + goal_matches = __insn_v1cmpeq (v, goal); + + if (__builtin_expect ((zero_matches | goal_matches) != 0, 0)) + break; + + v = vec_tolower (*++p); + } + + z = CFZ (zero_matches); + g = CFZ (goal_matches); + + /* If we found c before '\0' we got a match. Note that if c == '\0' + then g == z, and we correctly return the address of the '\0' + rather than NULL. */ + return (g <= z) ? ((char *) p) + (g >> 3) : NULL; +} + +# define vec_load(p) vec_tolower (*(p)) +# define STRCHR strcasechr +# define CMP_FUNC __strncasecmp + +#else + +# define vec_load(p) (*(p)) +# define STRCHR strchr +# define CMP_FUNC memcmp + +#endif + + +/* Compare 2-character needle using SIMD. */ +static char * +STRSTR2 (const char *haystack_start, const char *needle) +{ + int z, g; + + __insn_prefetch (haystack_start + 64); + + /* Get an aligned pointer. */ + const uintptr_t s_int = (uintptr_t) haystack_start; + const uint64_t *p = (const uint64_t *) (s_int & -8); + + /* Create eight copies of the first byte for which we are looking. */ + const uint64_t byte1 = copy_byte (TOLOWER (*needle)); + /* Create eight copies of the second byte for which we are looking. */ + const uint64_t byte2 = copy_byte (TOLOWER (*(needle + 1))); + + /* Read the first aligned word, but force bytes before the string to + match neither zero nor goal (we make sure the high bit of each byte + is 1, and the low 7 bits are all the opposite of the goal byte). */ + const uint64_t before_mask = MASK (s_int); + uint64_t v = + (vec_load (p) | before_mask) ^ (byte1 & __insn_v1shrui (before_mask, 1)); + + uint64_t zero_matches, goal_matches; + while (1) + { + /* Look for a terminating '\0'. */ + zero_matches = __insn_v1cmpeqi (v, 0); + uint64_t byte1_matches = __insn_v1cmpeq (v, byte1); + if (__builtin_expect (zero_matches, 0)) + { + /* This is the last vector. Don't worry about matches + crossing into the next vector. Shift the second byte + back 1 byte to align it with the first byte, then and to + check for both matching. Each vector has a 1 in the LSB + of the byte if there was match. */ + uint64_t byte2_matches = __insn_v1cmpeq (v, byte2); + goal_matches = byte1_matches & STRSHIFT (byte2_matches, 8); + break; + } + else + { + /* This is not the last vector, so load the next vector now. + And compare byte2 to the 8-bytes starting 1 byte shifted from v, + which goes 1-byte into the next vector. */ + uint64_t v2 = vec_load (p + 1); + if (byte1_matches) + { + /* 8-bytes starting 1 byte into v. */ + v = __insn_dblalign (v, v2, (void*)1); + uint64_t byte2_matches_shifted = __insn_v1cmpeq (v, byte2); + goal_matches = byte1_matches & byte2_matches_shifted; + if (__builtin_expect (goal_matches != 0, 0)) + break; + } + __insn_prefetch (p + 4); + /* Move to next vector. */ + v = v2; + p++; + } + } + + z = CFZ (zero_matches); + g = CFZ (goal_matches); + + /* If we found the match before '\0' we got a true match. Note that + if c == '\0' then g == z, and we correctly return the address of + the '\0' rather than NULL. */ + return (g <= z) ? ((char *) p) + (g >> 3) : NULL; +} + +/* Scan for NEEDLE, using the first two characters as a filter. */ +static char * +STRSTR_SCAN (const char *haystack, const char *needle, + unsigned int needle_len) +{ + char *match; + while (1) + { + match = STRSTR2 (haystack, needle); + if (match == NULL) + return NULL; + /* Found first two characters of needle, check for remainder. */ + if (CMP_FUNC (match + 2, needle + 2, needle_len - 2) == 0) + return match; + /* Move past the previous match. Could be +2 instead of +1 if + first two characters are different, but that tested slower. */ + haystack = match + 1; + } +} + +/* Return the first occurrence of NEEDLE in HAYSTACK. Return HAYSTACK + if NEEDLE is empty, otherwise NULL if NEEDLE is not found in + HAYSTACK. */ +char * +STRSTR (const char *haystack_start, const char *needle_start) +{ + const char *haystack = haystack_start; + const char *needle = needle_start; + __insn_prefetch (haystack); + size_t needle_len = strlen (needle_start); /* Length of NEEDLE. */ + size_t haystack_len; /* Known minimum length of HAYSTACK. */ + + if (needle_len <= 2) + { + if (needle_len == 1) + return STRCHR (haystack_start, *needle_start); + if (needle_len == 0) + return (char *) haystack_start; + else + return STRSTR2 (haystack_start, needle_start); + } + + /* Fail if NEEDLE is longer than HAYSTACK. */ + if (strnlen (haystack, needle_len) < needle_len) + return NULL; + + /* Perform the search. Abstract memory is considered to be an array + of 'unsigned char' values, not an array of 'char' values. See + ISO C 99 section 6.2.6.1. */ + if (needle_len < 40) + return STRSTR_SCAN (haystack_start, needle_start, needle_len); + else + { + /* Reduce the size of haystack using STRSTR2, since it has a smaller + linear coefficient than the Two-Way algorithm. */ + haystack = STRSTR2 (haystack_start, needle_start); + if (haystack == NULL) + return NULL; + needle = needle_start; + haystack_len = (haystack > haystack_start + needle_len ? 1 + : needle_len + haystack_start - haystack); + + return two_way_long_needle ((const unsigned char *) haystack, + haystack_len, + (const unsigned char *) needle, needle_len); + } +} +#ifndef USE_AS_STRCASESTR +libc_hidden_builtin_def (STRSTR) +#endif + +#undef LONG_NEEDLE_THRESHOLD |