27 lines
559 B
ArmAsm
27 lines
559 B
ArmAsm
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! _strnlen() Author: Kees J. Bot
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! 27 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 cx)
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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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__strnlen:
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push bp
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mov bp, sp
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push di
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mov di, 4(bp) ! di = string
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xorb al, al ! Look for a zero byte
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mov dx, cx ! Save maximum count
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cmpb cl, #1 ! 'Z' bit must be clear if cx = 0
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cld
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repne scasb ! Look for zero
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jne no0
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inc cx ! Don't count zero byte
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no0: mov ax, dx
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sub ax, cx ! Compute bytes scanned
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pop di
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pop bp
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ret
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