Texas Instruments MSP430x1xx manual Cmp.W, Cmp.B

Instruction Set

CMP[.W]	Compare source and destination
CMP.B	Compare source and destination
Syntax	CMP		src,dst or	CMP.W	src,dst
	CMP.B		src,dst
Operation	dst + .NOT.src + 1
	or
	(dst − src)
Description	The source operand is subtracted from the destination operand. This is
	accomplished by adding the 1s complement of the source operand plus 1. The
	two operands are not affected and the result is not stored; only the status bits
	are affected.
Status Bits	N: Set if result is negative, reset if positive (src >= dst)
	Z: Set if result is zero, reset otherwise (src = dst)
	C: Set if there is a carry from the MSB of the result, reset otherwise
	V: Set if an arithmetic overflow occurs, otherwise reset
Mode Bits	OSCOFF, CPUOFF, and GIE are not affected.
Example	R5 and R6 are compared. If they are equal, the program continues at the label
	EQUAL.
	CMP		R5,R6	; R5 = R6?
	JEQ		EQUAL	; YES, JUMP
Example	Two RAM blocks are compared. If they are not equal, the program branches
	to the label ERROR.
		MOV	#NUM,R5		; number of words to be compared
		MOV	#BLOCK1,R6		; BLOCK1 start address in R6
		MOV	#BLOCK2,R7		; BLOCK2 start address in R7
	L$1	CMP	@R6+,0(R7)		; Are Words equal? R6 increments
		JNZ	ERROR		; No, branch to ERROR
		INCD R7			; Increment R7 pointer
		DEC	R5		; Are all words compared?
		JNZ	L$1		; No, another compare
Example	The RAM bytes addressed by EDE and TONI are compared. If they are equal,
	the program continues at the label EQUAL.
		CMP.B EDE,TONI			; MEM(EDE) = MEM(TONI)?
		JEQ	EQUAL		; YES, JUMP

3-34 RISC 16−Bit CPU