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Instruction Set Description
4.6.3.26 RRAX
RRAX.A
Rotate right arithmetically the 20-bit operand
RRAX.[W]
Rotate right arithmetically the 16-bit operand
RRAX.B
Rotate right arithmetically the 8-bit operand
RRAX.A Rdst
Syntax
RRAX.W Rdst
RRAX Rdst
RRAX.B Rdst
RRAX.A dst
RRAX dst
or
RRAX.W dst
RRAX.B dst
Operation
MSB
→
MSB
→
MSB–1 ... LSB+1
→
LSB
→
C
Description
Register mode for the destination: the destination operand is shifted right by one bit
position as shown in
. The MSB retains its value (sign). The word instruction
RRAX.W clears the bits Rdst.19:16, the byte instruction RRAX.B clears the bits
Rdst.19:8. The MSB retains its value (sign), the LSB is shifted into the carry bit. RRAX
here operates equal to a signed division by 2.
All other modes for the destination: the destination operand is shifted right arithmetically
by one bit position as shown in
. The MSB retains its value (sign), the LSB
is shifted into the carry bit. RRAX here operates equal to a signed division by 2. All
addressing modes, with the exception of the Immediate mode, are possible in the full
memory.
Status Bits
N:
Set if result is negative, reset if positive
.A: dst.19 = 1, reset if dst.19 = 0
.W: dst.15 = 1, reset if dst.15 = 0
.B: dst.7 = 1, reset if dst.7 = 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 20-bit number in R5 is shifted arithmetically right four positions.
RPT
#4
RRAX.A
R5
; R5/16 -> R5
Example
The signed 8-bit value in EDE is multiplied by 0.5.
212
CPUX
SLAU272C – May 2011 – Revised November 2013
Copyright © 2011–2013, Texas Instruments Incorporated