| 1,44 → 1,34 |
|---|
| # strncmp() Author: Kees J. Bot 1 Jan 1994 |
| /* strncmp() Author: Kees J. Bot */ |
| /* 1 Jan 1994 */ |
| |
| # int strncmp(const char *s1, const char *s2, size_t ecx) |
| # Compare two strings. |
| # |
| /* int strncmp(const char *s1, const char *s2, size_t ecx) */ |
| /* Compare two strings. */ |
| /* */ |
| #include "asm.h" |
| |
| .intel_syntax |
| |
| .globl __strncmp |
| |
| .text |
| .align 16 |
| __strncmp: |
| push ebp |
| mov ebp, esp |
| |
| push esi |
| push edi |
| |
| test ecx, ecx # Max length is zero? |
| ENTRY(_strncmp) |
| push %ebp |
| movl %esp, %ebp |
| push %esi |
| push %edi |
| testl %ecx, %ecx /* Max length is zero? */ |
| je done |
| |
| mov esi, [ebp+8] # esi = string s1 |
| mov edi, [ebp+12] # edi = string s2 |
| movl 8(%ebp), %esi /* esi = string s1 */ |
| movl 12(%ebp), %edi /* edi = string s2 */ |
| cld |
| compare: |
| cmpsb # Compare two bytes |
| cmpsb /* Compare two bytes */ |
| jne done |
| |
| cmpb [esi-1], 0 # End of string? |
| cmpb $0, -1(%esi) /* End of string? */ |
| je done |
| |
| dec ecx # Length limit reached? |
| decl %ecx /* Length limit reached? */ |
| jne compare |
| done: |
| seta al # al = (s1 > s2) |
| setb ah # ah = (s1 < s2) |
| subb al, ah |
| movsx eax, al # eax = (s1 > s2) - (s1 < s2), i.e. -1, 0, 1 |
| |
| pop edi |
| pop esi |
| pop ebp |
| seta %al /* al = (s1 > s2) */ |
| setb %ah /* ah = (s1 < s2) */ |
| subb %ah, %al |
| movsbl %al, %eax /* eax = (s1 > s2) - (s1 < s2), i.e. -1, 0, 1 */ |
| pop %edi |
| pop %esi |
| pop %ebp |
| ret |