28 lines
584 B
ArmAsm
28 lines
584 B
ArmAsm
! _strnlen() Author: Kees J. Bot
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! 1 Jan 1994
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.sect .text; .sect .rom; .sect .data; .sect .bss
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! size_t _strnlen(const char *s, size_t ecx)
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! Return the length of a string.
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!
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.sect .text
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.define __strnlen
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.align 16
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__strnlen:
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push ebp
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mov ebp, esp
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push edi
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mov edi, 8(ebp) ! edi = string
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xorb al, al ! Look for a zero byte
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mov edx, ecx ! Save maximum count
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cmpb cl, 1 ! 'Z' bit must be clear if ecx = 0
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cld
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repne
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scasb ! Look for zero
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jne no0
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inc ecx ! Don't count zero byte
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no0: mov eax, edx
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sub eax, ecx ! Compute bytes scanned
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pop edi
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pop ebp
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ret
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