SW:		MOV AL, [SI]
		XOR AH, AH
		PUSH CX
		PUSH SI
		MOV CX, AX
		INC CX
		CLD
	REPZ	CMPSB
		POP SI
		POP CX
		JZ SW1
		XOR AX, AX
		STC
		RET
SW1:		ADD SI, AX
		INC SI
		CLC
		RET
