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-rw-r--r--sysdeps/tile/memchr.c77
1 files changed, 77 insertions, 0 deletions
diff --git a/sysdeps/tile/memchr.c b/sysdeps/tile/memchr.c
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+++ b/sysdeps/tile/memchr.c
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+/* Copyright (C) 2011-2017 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>
+#include "string-endian.h"
+
+void *
+__memchr (const void *s, int c, size_t n)
+{
+  const uint64_t *last_word_ptr;
+  const uint64_t *p;
+  const char *last_byte_ptr;
+  uintptr_t s_int;
+  uint64_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 uint64_t *) (s_int & -8);
+
+  /* Create eight copies of the byte for which we are looking. */
+  goal = copy_byte(c);
+
+  /* Read the first word, but munge it so that bytes before the array
+     will not match goal.  */
+  before_mask = MASK (s_int);
+  v = (*p | before_mask) ^ (goal & before_mask);
+
+  /* Compute the address of the last byte. */
+  last_byte_ptr = (const char *) s + n - 1;
+
+  /* Handle possible addition overflow.  */
+  if (__glibc_unlikely ((uintptr_t) last_byte_ptr < (uintptr_t) s))
+    last_byte_ptr = (const char *) UINTPTR_MAX;
+
+  /* Compute the address of the word containing the last byte. */
+  last_word_ptr = (const uint64_t *) ((uintptr_t) last_byte_ptr & -8);
+
+  while ((bits = v1cmpeq (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) + (CFZ (bits) >> 3);
+  return (ret <= last_byte_ptr) ? ret : NULL;
+}
+weak_alias (__memchr, memchr)
+libc_hidden_builtin_def (memchr)