Rev 1408 | Details | Compare with Previous | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
|---|---|---|---|
| 1627 | serge | 1 | /* strncmp() Author: Kees J. Bot */ |
| 2 | /* 1 Jan 1994 */ |
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| 1408 | serge | 3 | |
| 1627 | serge | 4 | /* int strncmp(const char *s1, const char *s2, size_t ecx) */ |
| 5 | /* Compare two strings. */ |
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| 6 | /* */ |
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| 7 | #include "asm.h" |
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| 1408 | serge | 8 | |
| 1627 | serge | 9 | ENTRY(_strncmp) |
| 10 | push %ebp |
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| 11 | movl %esp, %ebp |
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| 12 | push %esi |
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| 13 | push %edi |
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| 14 | testl %ecx, %ecx /* Max length is zero? */ |
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| 15 | je done |
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| 16 | movl 8(%ebp), %esi /* esi = string s1 */ |
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| 17 | movl 12(%ebp), %edi /* edi = string s2 */ |
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| 18 | cld |
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| 1408 | serge | 19 | compare: |
| 1627 | serge | 20 | cmpsb /* Compare two bytes */ |
| 21 | jne done |
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| 22 | cmpb $0, -1(%esi) /* End of string? */ |
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| 23 | je done |
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| 24 | decl %ecx /* Length limit reached? */ |
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| 25 | jne compare |
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| 1408 | serge | 26 | done: |
| 1627 | serge | 27 | seta %al /* al = (s1 > s2) */ |
| 28 | setb %ah /* ah = (s1 < s2) */ |
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| 29 | subb %ah, %al |
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| 30 | movsbl %al, %eax /* eax = (s1 > s2) - (s1 < s2), i.e. -1, 0, 1 */ |
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| 31 | pop %edi |
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| 32 | pop %esi |
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| 33 | pop %ebp |
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| 34 | ret |