Address Instructions
4-163
16-Bit MSP430X CPU
CMPA
Compare the 20-bit source with a 20-bit destination register
Syntax
CMPA
Rsrc,Rdst
CMPA
#imm20,Rdst
Operation
(.not. src) + 1 + Rdst
or Rdst − src
Description
The 20-bit source operand is subtracted from the 20-bit destination CPU
register. This is made by adding the 1’s complement of the 1 to the
destination register. The result affects only the status bits.
Status Bits
N:
Set if result is negative (src > dst), reset if positive (src <= dst)
Z:
Set if result is zero (src = dst), reset otherwise (src
≠
dst)
C:
Set if there is a carry from the MSB, reset otherwise
V:
Set if the subtraction of a negative source operand from a positive
destination operand delivers a negative result, or if the subtraction of
a positive source operand from a negative destination operand delivers
a positive result, reset otherwise (no overflow).
Mode Bits
OSCOFF, CPUOFF, and GIE are not affected.
Example
A 20-bit immediate operand and R6 are compared. If they are equal the
program continues at label EQUAL.
CMPA
#12345h,R6
; Compare R6 with 12345h
JEQ
EQUAL
; R5 = 12345h
...
; Not equal
Example
The 20-bit values in R5 and R6 are compared. If R5 is greater than (signed) or
equal to R6, the program continues at label GRE.
CMPA
R6,R5
; Compare R6 with R5 (R5 − R6)
JGE
GRE
; R5 >= R6
...
; R5 < R6
Summary of Contents for MSP430x4xx Family
Page 1: ...MSP430x4xx Family 2007 Mixed Signal Products User s Guide SLAU056G ...
Page 2: ......
Page 6: ...vi ...
Page 114: ...3 76 RISC 16 Bit CPU ...
Page 304: ...5 20 FLL Clock Module ...
Page 340: ...7 8 Supply Voltage Supervisor ...
Page 348: ...8 8 16 Bit Hardware Multiplier ...
Page 372: ...9 24 32 Bit Hardware Multiplier ...
Page 400: ...10 28 DMA Controller ...
Page 428: ...13 10 Basic Timer1 ...
Page 466: ...15 24 Timer_A ...
Page 522: ...17 30 USART Peripheral Interface UART Mode ...
Page 544: ...18 22 USART Peripheral Interface SPI Mode ...
Page 672: ...23 12 Comparator_A ...
Page 692: ...24 20 LCD Controller ...
Page 746: ...26 28 ADC12 ...