strncat: shorter version for i386, add small embedded test

memchr: add small embedded test
strnlen: make small embedded test easier to use
strncmp: reformat assembly to make it readable, no code changes
 (verified with objdump)

    text           data     bss     dec     hex filename
-     46              0       0      46      2e libc/string/i386/strncat.os
+     39              0       0      39      27 libc/string/i386/strncat.os

1 files changed, 21 insertions, 20 deletions

diff --git a/libc/string/i386/strncmp.c b/libc/string/i386/strncmp.c
index a14bb503b..bfb20c307 100644
--- a/libc/string/i386/strncmp.c
+++ b/libc/string/i386/strncmp.c
@@ -32,27 +32,28 @@
 
 #include <string.h>
 
-/* Experimentally off - libc_hidden_proto(strncmp) */
+#undef strncmp
 int strncmp(const char *cs, const char *ct, size_t count)
 {
-    register int __res;
-    int d0, d1, d2;
-    __asm__ __volatile__(
-	    "incl %3\n"
-	    "1:\tdecl %3\n\t"
-	    "jz 2f\n"
-	    "lodsb\n\t"
-	    "scasb\n\t"
-	    "jne 3f\n\t"
-	    "testb %%al,%%al\n\t"
-	    "jne 1b\n"
-	    "2:\txorl %%eax,%%eax\n\t"
-	    "jmp 4f\n"
-	    "3:\tsbbl %%eax,%%eax\n\t"
-	    "orb $1,%%al\n"
-	    "4:"
-	    :"=a" (__res), "=&S" (d0), "=&D" (d1), "=&c" (d2)
-	    :"1" (cs),"2" (ct),"3" (count));
-    return __res;
+	int eax;
+	int esi, edi, ecx;
+	__asm__ __volatile__(
+		"	incl	%%ecx\n"
+		"1:	decl	%%ecx\n"
+		"	jz	2f\n"
+		"	lodsb\n"
+		"	scasb\n"
+		"	jne	3f\n"
+		"	testb	%%al, %%al\n"
+		"	jnz	1b\n"
+		"2:	xorl	%%eax, %%eax\n"
+		"	jmp	4f\n"
+		"3:	sbbl	%%eax, %%eax\n"
+		"	orb	$1, %%al\n"
+		"4:\n"
+		: "=a" (eax), "=&S" (esi), "=&D" (edi), "=&c" (ecx)
+		: "1" (cs), "2" (ct), "3" (count)
+	);
+	return eax;
 }
 libc_hidden_weak(strncmp)