Texas Instruments MSP430x1xx - Manual (Page 375)

Instruction Set Overview
B-25 Instruction Set Description
* DEC[.W] Decrement destination
* DEC.B Decrement destination
Syntax DEC dst or DEC.W dst
DEC.B dst
Operation dst – 1 –> dst
Emulation SUB #1,dst
Emulation SUB.B #1,dst
Description The destination operand is decremented by one. The original contents are
lost.
Status Bits N: Set if result is negative, reset if positive
Z: Set if dst contained 1, reset otherwise
C: Reset if dst contained 0, set otherwise
V: Set if an arithmetic overflow occurs, otherwise reset.
Set if initial value of destination was 08000h, otherwise reset.
Set if initial value of destination was 080h, otherwise reset.
Mode Bits OscOff, CPUOff, and GIE are not affected.