! strncmp() Author: Kees J. Bot ! 1 Jan 1994 .sect .text; .sect .rom; .sect .data; .sect .bss ! int strncmp(const char *s1, const char *s2, size_t ecx) ! Compare two strings. ! .sect .text .define __strncmp .align 16 __strncmp: push ebp mov ebp, esp push esi push edi test ecx, ecx ! Max length is zero? je done mov esi, 8(ebp) ! esi = string s1 mov edi, 12(ebp) ! edi = string s2 cld compare: cmpsb ! Compare two bytes jne done cmpb -1(esi), 0 ! End of string? je done dec ecx ! Length limit reached? jne compare done: seta al ! al = (s1 > s2) setb ah ! ah = (s1 < s2) subb al, ah movsxb eax, al ! eax = (s1 > s2) - (s1 < s2), i.e. -1, 0, 1 pop edi pop esi pop ebp ret