MSP430 Instructions
4-101
16-Bit MSP430X CPU
RRA[.W]
Rotate Right Arithmetically destination word
RRA.B
Rotate Right Arithmetically destination byte
Syntax
RRA.B
dst or RRA.W dst
Operation
MSB
→
MSB
→
MSB
-
1 .
→
... LSB+1
→
LSB
→
C
Description
The destination operand is shifted right arithmetically by one bit position as
shown in Figure 4−40. The MSB retains its value (sign). RRA operates equal to
a signed division by 2. The MSB is retained and shifted into the MSB
-
1. The
LSB+1 is shifted into the LSB. The previous LSB is shifted into the carry bit C.
Status Bits
N:
Set if result is negative (MSB = 1), reset otherwise (MSB = 0)
Z:
Set if result is zero, reset otherwise
C:
Loaded from the LSB
V: Reset
Mode Bits
OSCOFF, CPUOFF, and GIE are not affected.
Example
The signed 16-bit number in R5 is shifted arithmetically right one position.
RRA
R5
; R5/2 -> R5
Example
The signed RAM byte EDE is shifted arithmetically right one position.
RRA.B
EDE
; EDE/2 -> EDE
Figure 4−40. Rotate Right Arithmetically RRA.B and RRA.W
C
19
0
MSB
0
0
0
0
0
0
0
7
15
0
0
0
0
0
LSB
C
19
0
MSB
0
0
0
0
15
LSB
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 ...