strncmp.s

ICCAVR中所有的库函数源码

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;
; char *strncmp(char *s1, char *s2, size_t bytes)
;
_strncmp::
	ldd	R24,Y+0	; load length
	ldd	R25,Y+1
	cpi	R24,0
	cpc	R25,R24
	 breq	strncmpeq	; length == 0
	mov	R27,R17	; move pointers
	mov	R26,R16
	mov	R31,R19
	mov	R30,R18
strncmp1:			; compare
	ld	R16,X+
	ld	R17,Z+
	sub	R16,R17
	 brne	strncmpx	; mismatch ...
	tst	R17
	 breq	strncmpeq	; end of strings ...
	sbiw	R24,1
	 brne	strncmp1	; more ...
	;			; else strings are EQ
strncmpeq:
	ldi	R16,0
strncmpx:
	ldi	R17,0
	sbrc	R16,7
	 com	R17
	ret
;
;<eof; 2003-08-01 ja>