diff options
Diffstat (limited to 'libc/string/i386/strncpy.c')
| -rw-r--r-- | libc/string/i386/strncpy.c | 55 |
1 files changed, 37 insertions, 18 deletions
diff --git a/libc/string/i386/strncpy.c b/libc/string/i386/strncpy.c index 76aa6ae1b..ba0c41063 100644 --- a/libc/string/i386/strncpy.c +++ b/libc/string/i386/strncpy.c @@ -32,25 +32,44 @@ #include <string.h> -/* Experimentally off - libc_hidden_proto(strncpy) */ +#undef strncpy +//#define strncpy TESTING char *strncpy(char * dest, const char * src, size_t count) { - int d0, d1, d2, d3; - __asm__ __volatile__( - "incl %2\n" - "1:\n" - "decl %2\n" - "jz 2f\n" - "lodsb\n\t" - "stosb\n\t" - "testb %%al,%%al\n\t" - "jne 1b\n\t" - "decl %2\n" - "rep\n\t" - "stosb\n" - "2:" - : "=&S" (d0), "=&D" (d1), "=&c" (d2), "=&a" (d3) - :"0" (src),"1" (dest),"2" (count) : "memory"); - return dest; + int esi, edi, ecx, eax; + __asm__ __volatile__( + "1: subl $1, %%ecx\n" /* not dec! it doesnt set CF */ + " jc 2f\n" + " lodsb\n" + " stosb\n" + " testb %%al, %%al\n" + " jnz 1b\n" + " rep; stosb\n" + "2:\n" + : "=&S" (esi), "=&D" (edi), "=&c" (ecx), "=&a" (eax) + : "0" (src), "1" (dest), "2" (count) + : "memory" + ); + return dest; } +#ifndef strncpy libc_hidden_def(strncpy) +#else +/* Uncomment TESTING, gcc -D_GNU_SOURCE -m32 -Os strncpy.c -o strncpy + * and run ./strncpy + */ +int main() +{ + static char str[99]; + + str[3] = '*'; str[4] = 0; strncpy(str, "abc", 3); + printf(strcmp(str, "abc*") == 0 ? "ok\n" : "BAD!\n"); + + str[4] = '*'; str[5] = '+'; strncpy(str, "abc", 5); + printf(strcmp(str, "abc") == 0 && str[4] == 0 && str[5] == '+' ? + "ok\n" : "BAD!\n"); + strncpy(str, "abc", 0); /* should do nothing */ + printf(strcmp(str, "abc") == 0 && str[4] == 0 && str[5] == '+' ? + "ok\n" : "BAD!\n"); +} +#endif |