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

diff --git a/libc/string/i386/memchr.c b/libc/string/i386/memchr.c
index bff0538d77ae593691fea83c8926e20b383d0f80..772251cee54c2adedf9229ae89870f23697019ea 100644 (file)
--- a/libc/string/i386/memchr.c
+++ b/libc/string/i386/memchr.c
@@ -33,6 +33,7 @@
 #include <string.h>
 
 #undef memchr
+//#define memchr TESTING
 void *memchr(const void *s, int c, size_t count)
 {
        void *edi;
@@ -51,4 +52,24 @@ void *memchr(const void *s, int c, size_t count)
        );
        return edi;
 }
+#ifndef memchr
 libc_hidden_def(memchr)
+#else
+/* Uncomment TESTING, gcc -D__USE_GNU -m32 -Os memchr.c -o memchr
+ * and run ./memchr
+ */
+int main()
+{
+       static const char str[] = "abc.def";
+       printf((char*)memchr(str, '.',-2) - str == 3 ? "ok\n" : "BAD!\n");
+       printf((char*)memchr(str, '.',-1) - str == 3 ? "ok\n" : "BAD!\n");
+       printf((char*)memchr(str, '.', 0) == NULL    ? "ok\n" : "BAD!\n");
+       printf((char*)memchr(str, '.', 1) == NULL    ? "ok\n" : "BAD!\n");
+       printf((char*)memchr(str, '.', 2) == NULL    ? "ok\n" : "BAD!\n");
+       printf((char*)memchr(str, '.', 3) == NULL    ? "ok\n" : "BAD!\n");
+       printf((char*)memchr(str, '.', 4) - str == 3 ? "ok\n" : "BAD!\n");
+       printf((char*)memchr(str, '.', 5) - str == 3 ? "ok\n" : "BAD!\n");
+       printf((char*)memchr(str+3, '.', 0) == NULL    ? "ok\n" : "BAD!\n");
+       printf((char*)memchr(str+3, '.', 5) - str == 3 ? "ok\n" : "BAD!\n");
+}
+#endif

diff --git a/libc/string/i386/strncat.c b/libc/string/i386/strncat.c
index 3872679d589794db3f0fddba87bda7e644dab396..640b0d213e9ec2c2814e5b8d0ce066f63b5bfc34 100644 (file)
--- a/libc/string/i386/strncat.c
+++ b/libc/string/i386/strncat.c
@@ -32,30 +32,55 @@
 
 #include <string.h>
 
-/* Experimentally off - libc_hidden_proto(strncat) */
-char *strncat(char * dest,
-       const char * src, size_t count)
+#undef strncat
+//#define strncat TESTING
+char *strncat(char * dest, const char * src, size_t count)
 {
-    int d0, d1, d2, d3;
-    __asm__ __volatile__(
-           "repne\n\t"
-           "scasb\n\t"
-           "decl %1\n\t"
-           "movl %8,%3\n"
-           "incl %3\n"
-           "1:\tdecl %3\n\t"
-           "jz 2f\n"
-           "lodsb\n\t"
-           "stosb\n\t"
-           "testb %%al,%%al\n\t"
-           "jne 1b\n"
-           "jmp 3f\n"
-           "2:\txorl %2,%2\n\t"
-           "stosb\n"
-           "3:"
-           : "=&S" (d0), "=&D" (d1), "=&a" (d2), "=&c" (d3)
-           : "0" (src),"1" (dest),"2" (0),"3" (0xffffffff), "g" (count)
-           : "memory");
-    return dest;
+       int esi, edi, eax, ecx, edx;
+       __asm__ __volatile__(
+               "       xorl    %%eax, %%eax\n"
+               "       incl    %%edx\n"
+               "       pushl   %%edi\n" /* save dest */
+               "       repne; scasb\n"
+               "       decl    %%edi\n" /* edi => NUL in dest */
+               /* count-- */
+               "1:     decl    %%edx\n"
+               /* if count reached 0, store NUL and bail out */
+               "       movl    %%edx, %%eax\n"
+               "       jz      2f\n"
+               /* else copy a char */
+               "       lodsb\n"
+               "2:     stosb\n"
+               "       testb   %%al, %%al\n"
+               "       jnz     1b\n"
+               /* end of loop */
+               "       popl    %%eax\n" /* restore dest into eax */
+               : "=&S" (esi), "=&D" (edi), "=&a" (eax), "=&c" (ecx), "=&d" (edx)
+               : "0" (src), "1" (dest), "3" (0xffffffff), "4" (count)
+               : "memory"
+       );
+       return (char *)eax;
 }
+#ifndef strncat
 libc_hidden_def(strncat)
+#else
+/* Uncomment TESTING, gcc -m32 -Os strncat.c -o strncat
+ * and run ./strncat
+ */
+int main()
+{
+       char buf[99];
+
+       strcpy(buf, "abc"); buf[4] = '*'; strncat(buf, "def", 0);
+       printf(strcmp(buf, "abc") == 0 && buf[4] == '*' ? "ok\n" : "BAD!\n");
+
+       strcpy(buf, "abc"); buf[6] = 1; buf[7] = '*'; strncat(buf, "def", 50);
+       printf(strcmp(buf, "abcdef") == 0 && buf[7] == '*' ? "ok\n" : "BAD!\n");
+
+       strcpy(buf, "abc"); buf[6] = 1; buf[7] = '*'; strncat(buf, "def", -1);
+       printf(strcmp(buf, "abcdef") == 0 && buf[7] == '*' ? "ok\n" : "BAD!\n");
+
+       strcpy(buf, "abc"); buf[6] = 1; buf[7] = '*'; strncat(buf, "def123", 3);
+       printf(strcmp(buf, "abcdef") == 0 && buf[7] == '*' ? "ok\n" : "BAD!\n");
+}
+#endif

diff --git a/libc/string/i386/strncmp.c b/libc/string/i386/strncmp.c
index a14bb503bcc55303f39f1943c674d1f74cc54c2c..bfb20c30791cd2b010e8e3591809ff32e9b823e9 100644 (file)
--- 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)

diff --git a/libc/string/i386/strnlen.c b/libc/string/i386/strnlen.c
index 066a11ef78d6d4ddef0694b6792b85f7b8bd1474..d9bce648562a7eba98d2de3aea4d04f924305773 100644 (file)
--- a/libc/string/i386/strnlen.c
+++ b/libc/string/i386/strnlen.c
@@ -34,6 +34,8 @@
 
 #ifdef __USE_GNU
 
+#undef strnlen
+//#define strnlen TESTING
 size_t strnlen(const char *s, size_t count)
 {
        int edx;
@@ -51,20 +53,22 @@ size_t strnlen(const char *s, size_t count)
        );
        return eax;
 }
+#ifndef strnlen
 libc_hidden_def(strnlen)
-
-#if 0
+#else
+/* Uncomment TESTING, gcc -D__USE_GNU -m32 -Os strnlen.c -o strnlen
+ * and run ./strnlen
+ */
 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;
+       printf(strnlen("abc\0def", -2) == 3 ? "ok\n" : "BAD!\n");
+       printf(strnlen("abc\0def", -1) == 3 ? "ok\n" : "BAD!\n");
+       printf(strnlen("abc\0def", 0) == 0 ? "ok\n" : "BAD!\n");
+       printf(strnlen("abc\0def", 1) == 1 ? "ok\n" : "BAD!\n");
+       printf(strnlen("abc\0def", 2) == 2 ? "ok\n" : "BAD!\n");
+       printf(strnlen("abc\0def", 3) == 3 ? "ok\n" : "BAD!\n");
+       printf(strnlen("abc\0def", 4) == 3 ? "ok\n" : "BAD!\n");
+       printf(strnlen("abc\0def", 5) == 3 ? "ok\n" : "BAD!\n");
 }
 #endif