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author | Joseph Myers <joseph@codesourcery.com> | 2012-07-01 13:06:41 +0000 |
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committer | Joseph Myers <joseph@codesourcery.com> | 2012-07-01 13:06:41 +0000 |
commit | e64ac02c24b43659048622714afdc92fedf561fa (patch) | |
tree | 37162878b72d302de351788bec4c9360c9d55f1d /ports/sysdeps/tile/tilepro/memchr.c | |
parent | a20c2b3c87aebc7d4b090c622d36480263b80042 (diff) | |
download | glibc-e64ac02c24b43659048622714afdc92fedf561fa.tar.gz |
Move all files into ports/ subdirectory in preparation for merge with glibcglibc-2.16-ports-before-merge
Diffstat (limited to 'ports/sysdeps/tile/tilepro/memchr.c')
-rw-r--r-- | ports/sysdeps/tile/tilepro/memchr.c | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/ports/sysdeps/tile/tilepro/memchr.c b/ports/sysdeps/tile/tilepro/memchr.c new file mode 100644 index 0000000000..abf4bbadf6 --- /dev/null +++ b/ports/sysdeps/tile/tilepro/memchr.c @@ -0,0 +1,72 @@ +/* Copyright (C) 2011 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011. + + 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 <string.h> +#include <stdint.h> + +void * +__memchr (const void *s, int c, size_t n) +{ + const uint32_t *last_word_ptr; + const uint32_t *p; + const char *last_byte_ptr; + uintptr_t s_int; + uint32_t goal, before_mask, v, bits; + char *ret; + + if (__builtin_expect (n == 0, 0)) + { + /* Don't dereference any memory if the array is empty. */ + return NULL; + } + + /* Get an aligned pointer. */ + s_int = (uintptr_t) s; + p = (const uint32_t *) (s_int & -4); + + /* Create four copies of the byte for which we are looking. */ + goal = 0x01010101 * (uint8_t) c; + + /* Read the first word, but munge it so that bytes before the array + will not match goal. Note that this shift count expression works + because we know shift counts are taken mod 32. */ + before_mask = (1 << (s_int << 3)) - 1; + v = (*p | before_mask) ^ (goal & before_mask); + + /* Compute the address of the last byte. */ + last_byte_ptr = (const char *) s + n - 1; + + /* Compute the address of the word containing the last byte. */ + last_word_ptr = (const uint32_t *) ((uintptr_t) last_byte_ptr & -4); + + while ((bits = __insn_seqb (v, goal)) == 0) + { + if (__builtin_expect (p == last_word_ptr, 0)) + { + /* We already read the last word in the array, so give up. */ + return NULL; + } + v = *++p; + } + + /* We found a match, but it might be in a byte past the end of the array. */ + ret = ((char *) p) + (__insn_ctz (bits) >> 3); + return (ret <= last_byte_ptr) ? ret : NULL; +} +weak_alias (__memchr, memchr) +libc_hidden_builtin_def (memchr) |