Index: libc/machine/i386/strlen.S
===================================================================
RCS file: /cvs/src/src/newlib/libc/machine/i386/strlen.S,v
retrieving revision 1.3
diff -u -p -r1.3 strlen.S
--- libc/machine/i386/strlen.S	20 Dec 2002 21:31:19 -0000	1.3
+++ libc/machine/i386/strlen.S	22 May 2008 12:47:22 -0000
@@ -1,6 +1,6 @@
 /*
  * ====================================================
- * Copyright (C) 1998, 2002 by Red Hat Inc. All rights reserved.
+ * Copyright (C) 1998, 2002, 2008 by Red Hat Inc. All rights reserved.
  *
  * Permission to use, copy, modify, and distribute this
  * software is freely granted, provided that this notice
@@ -20,12 +20,75 @@ SYM (strlen):
 	pushl edi
 	movl 8(ebp),edx
 
+#ifdef __OPTIMIZE_SIZE__
 	cld
 	movl edx,edi
 	movl $4294967295,ecx
 	xor eax,eax
 	repnz
 	scasb
+#else
+/* Modern x86 hardware is much faster at double-word
+   manipulation than with bytewise repnz scasb.  */
+
+/* Do byte-wise checks until string is aligned.  */
+	movl edx,edi
+	test $3,edi
+	je L5
+	movb (edi),cl
+	incl edi
+	testb cl,cl
+	je L15
+
+	test $3,edi
+	je L5
+	movb (edi),cl
+	incl edi
+	testb cl,cl
+	je L15
+
+	test $3,edi
+	je L5
+	movb (edi),cl
+	incl edi
+	testb cl,cl
+	je L15
+
+L5:
+	subl $4,edi
+
+/* loop performing 4 byte mask checking for desired 0 byte */
+	.p2align 4,,7
+L10:
+	addl $4,edi
+	movl (edi),ecx
+	leal -16843009(ecx),eax
+	notl ecx
+	andl ecx,eax
+	testl $-2139062144,eax
+	je L10
+
+/* Find which of four bytes is 0.  */
+	notl ecx
+	incl edi
+
+	testb cl,cl
+	je L15
+	incl edi
+	shrl $8,ecx
+
+	testb cl,cl
+	je L15
+	incl edi
+	shrl $8,ecx
+
+	testb cl,cl
+	je L15
+	incl edi
+
+#endif
+
+L15:
 	subl edx,edi
 	leal -1(edi),eax
 
Index: libc/string/strlen.c
===================================================================
RCS file: /cvs/src/src/newlib/libc/string/strlen.c,v
retrieving revision 1.1.1.1
diff -u -p -r1.1.1.1 strlen.c
--- libc/string/strlen.c	17 Feb 2000 19:39:48 -0000	1.1.1.1
+++ libc/string/strlen.c	22 May 2008 12:47:22 -0000
@@ -1,7 +1,7 @@
-/* 
+/*
 FUNCTION
 	<<strlen>>---character string length
-	
+
 INDEX
 	strlen
 
@@ -57,32 +57,32 @@ size_t
 _DEFUN (strlen, (str),
 	_CONST char *str)
 {
-#if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
   _CONST char *start = str;
 
-  while (*str)
-    str++;
-
-  return str - start;
-#else
-  _CONST char *start = str;
+#if !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__)
   unsigned long *aligned_addr;
 
-  if (!UNALIGNED (str))
+  /* Align the pointer, so we can search a word at a time.  */
+  while (UNALIGNED (str))
     {
-      /* If the string is word-aligned, we can check for the presence of 
-         a null in each word-sized block.  */
-      aligned_addr = (unsigned long*)str;
-      while (!DETECTNULL (*aligned_addr))
-        aligned_addr++;
-
-      /* Once a null is detected, we check each byte in that block for a
-         precise position of the null.  */
-      str = (char*)aligned_addr;
+      if (!*str)
+	return str - start;
+      str++;
     }
- 
+
+  /* If the string is word-aligned, we can check for the presence of
+     a null in each word-sized block.  */
+  aligned_addr = (unsigned long *)str;
+  while (!DETECTNULL (*aligned_addr))
+    aligned_addr++;
+
+  /* Once a null is detected, we check each byte in that block for a
+     precise position of the null.  */
+  str = (char *) aligned_addr;
+
+#endif /* not PREFER_SIZE_OVER_SPEED */
+
   while (*str)
     str++;
   return str - start;
-#endif /* not PREFER_SIZE_OVER_SPEED */
 }