strlen.s

来自「操作系统SunOS 4.1.3版本的源码」· S 代码 · 共 25 行

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/*	.asciz "@(#)strlen.s 1.1 92/07/30 SMI"	*/
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#include "DEFS.h"

| Usage: strlen(s)
| Returns the number of
| non-NULL bytes in string argument.

ENTRY(strlen)
	movl	PARAM,a0	| s
	movl	a0,a1		| pointer for scanning

	moveq	#-1,d1		| count of 65535
| The following loop runs in loop mode on 68010
1$:	tstb	a1@+		| find the terminating null for s1
	dbeq	d1,1$
	bne	1$		| not zero yet - keep going

	subql	#1,a1		| point to the null
	subl	a0,a1		| get the length
	movl	a1,d0		| and return it
	RET