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authorRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
committerRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
commit28f540f45bbacd939bfd07f213bcad2bf730b1bf (patch)
tree15f07c4c43d635959c6afee96bde71fb1b3614ee /sysdeps/i386/strlen.c
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diff --git a/sysdeps/i386/strlen.c b/sysdeps/i386/strlen.c
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+/* strlen -- determine the length of a string.
+   For Intel 80x86, x>=3.
+   Copyright (C) 1991, 1992, 1993 Free Software Foundation, Inc.
+   Contributed by Torbjorn Granlund (tege@sics.se).
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <ansidecl.h>
+#include <string.h>
+
+size_t
+DEFUN(strlen, (str), CONST char *str)
+{
+  int cnt;
+
+  asm("cld\n"			/* Search forward.  */
+      /* Some old versions of gas need `repne' instead of `repnz'.  */
+      "repnz\n"			/* Look for a zero byte.  */
+      "scasb" /* %0, %1, %3 */ :
+      "=c" (cnt) : "D" (str), "0" (-1), "a" (0));
+
+  return -2 - cnt;
+}