1 files changed, 57 insertions, 0 deletions
diff --git a/sysdeps/tile/strnlen.c b/sysdeps/tile/strnlen.c
new file mode 100644
index 0000000000..c3560d208d
--- /dev/null
+++ b/sysdeps/tile/strnlen.c
@@ -0,0 +1,57 @@
+/* Copyright (C) 2013-2017 Free Software Foundation, Inc.
+   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 <string.h>
+#include <stdint.h>
+#include "string-endian.h"
+
+/* Find the length of S, but scan at most MAXLEN characters.  If no
+   '\0' terminator is found in that many characters, return MAXLEN.  */
+size_t
+__strnlen (const char *s, size_t maxlen)
+{
+  /* When maxlen is 0, can't read any bytes or it might cause a page fault.  */
+  if (maxlen == 0)
+    return 0;
+
+  /* Get an aligned pointer. */
+  const uintptr_t s_int = (uintptr_t) s;
+  const uint64_t *p = (const uint64_t *) (s_int & -8);
+  size_t bytes_read = sizeof (*p) - (s_int & (sizeof (*p) - 1));
+
+  /* Read and MASK the first word. */
+  uint64_t v = *p | MASK (s_int);
+
+  uint64_t bits;
+  while ((bits = v1cmpeqi (v, 0)) == 0)
+    {
+      if (bytes_read >= maxlen)
+	{
+	  /* Read maxlen bytes and didn't find the terminator. */
+	  return maxlen;
+	}
+      v = *++p;
+      bytes_read += sizeof (v);
+    }
+
+  /* Found '\0', check it is not larger than maxlen */
+  size_t len = ((const char *) p) + (CFZ (bits) >> 3) - s;
+  return (len < maxlen ? len : maxlen);
+}
+libc_hidden_def (__strnlen)
+weak_alias (__strnlen, strnlen)
+libc_hidden_def (strnlen)