From f3f7db016abb60cbfbdc5c4ffda376f5a90587ab Mon Sep 17 00:00:00 2001
From: Denis Vlasenko <vda.linux@googlemail.com>
Date: Fri, 19 Dec 2008 00:25:56 +0000
Subject: string/i386: smaller, and hopefully easier to read, strnlen().
text data bss dec hex filename
- 25 0 0 25 19 libc/string/i386/strnlen.os
+ 24 0 0 24 18 libc/string/i386/strnlen.os
---
libc/string/i386/strnlen.c | 47 ++++++++++++++++++++++++++++++----------------
1 file changed, 31 insertions(+), 16 deletions(-)
(limited to 'libc/string/i386')
diff --git a/libc/string/i386/strnlen.c b/libc/string/i386/strnlen.c
index 02c72f530..066a11ef7 100644
--- a/libc/string/i386/strnlen.c
+++ b/libc/string/i386/strnlen.c
@@ -33,24 +33,39 @@
#include <string.h>
#ifdef __USE_GNU
-/* Experimentally off - libc_hidden_proto(strnlen) */
+
size_t strnlen(const char *s, size_t count)
{
- int d0;
- register int __res;
- __asm__ __volatile__(
- "movl %2,%0\n\t"
- "incl %1\n"
- "jmp 2f\n"
- "1:\tcmpb $0,(%0)\n\t"
- "je 3f\n\t"
- "incl %0\n"
- "2:\tdecl %1\n\t"
- "jne 1b\n"
- "3:\tsubl %2,%0"
- :"=a" (__res), "=&d" (d0)
- :"c" (s),"1" (count));
- return __res;
+ int edx;
+ int eax;
+ __asm__ __volatile__(
+ " leal -1(%%ecx), %%eax\n"
+ "1: incl %%eax\n"
+ " decl %%edx\n"
+ " jz 3f\n"
+ " cmpb $0, (%%eax)\n"
+ " jnz 1b\n"
+ "3: subl %%ecx, %%eax"
+ : "=a" (eax), "=&d" (edx)
+ : "c" (s), "1" (count + 1)
+ );
+ return eax;
}
libc_hidden_def(strnlen)
+
+#if 0
+int main()
+{
+ printf(strnlen2("abc\0def", -2) == 3 ? "ok\n" : "BAD!\n");
+ printf(strnlen2("abc\0def", -1) == 3 ? "ok\n" : "BAD!\n");
+ printf(strnlen2("abc\0def", 0) == 0 ? "ok\n" : "BAD!\n");
+ printf(strnlen2("abc\0def", 1) == 1 ? "ok\n" : "BAD!\n");
+ printf(strnlen2("abc\0def", 2) == 2 ? "ok\n" : "BAD!\n");
+ printf(strnlen2("abc\0def", 3) == 3 ? "ok\n" : "BAD!\n");
+ printf(strnlen2("abc\0def", 4) == 3 ? "ok\n" : "BAD!\n");
+ printf(strnlen2("abc\0def", 5) == 3 ? "ok\n" : "BAD!\n");
+ return 0;
+}
+#endif
+
#endif
--
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