Texas Instruments MSP430x1xx manual Sbc.B

Instruction Set

* SBC[.W]	Subtract source and borrow/.NOT. carry from destination
* SBC.B	Subtract source and borrow/.NOT. carry from destination
Syntax	SBC	dst	or	SBC.W dst
	SBC.B	dst
Operation	dst + 0FFFFh + C −> dst
	dst + 0FFh + C −> dst
Emulation	SUBC	#0,dst
	SUBC.B	#0,dst
Description	The carry bit (C) is added to the destination operand minus one. The previous
	contents of the destination are lost.
Status Bits	N: Set if result is negative, reset if positive
	Z: Set if result is zero, reset otherwise

C:Set if there is a carry from the MSB of the result, reset otherwise. Set to 1 if no borrow, reset if borrow.

V: Set if an arithmetic overflow occurs, reset otherwise.

Mode Bits	OSCOFF, CPUOFF, and GIE are not affected.
Example	The 16-bit counter pointed to by R13 is subtracted from a 32-bit counter
	pointed to by R12.
	SUB	@R13,0(R12)	; Subtract LSDs
	SBC	2(R12)	; Subtract carry from MSD
Example	The 8-bit counter pointed to by R13 is subtracted from a 16-bit counter pointed
	to by R12.
	SUB.B	@R13,0(R12)	; Subtract LSDs
	SBC.B	1(R12)	; Subtract carry from MSD

Note: Borrow Implementation.
The borrow is treated as a .NOT. carry : Borrow	Carry bit
Yes	0
No	1

3-62 RISC 16−Bit CPU