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INSTRUCTION DESCRIPTIONS
A - 38 INSTRUCTION SET DETAILS MOTOROLA
Assembler Syntax: ASR D (parallel move)
Description: Arithmetically shift the destination operand D one bit to the right and store
the result in the destination accumulator. The LS bit of D prior to instruction execution is
shifted into the carry bit C, and the MS bit of D is held constant.
Example:
:
ASR B X:–(R3),R3 ;divide B by 2, update R3, load R3
:
Explanation of Example: Prior to execution, the 56-bit B accumulator contains the
value $A8:A86420:A86421. The execution of the ASR B instruction shifts the 56-bit
value in the B accumulator one bit to the right and stores the result back in the B accu-
mulator.
ASR Arithmetic Shift Accumulator Right ASR
55 47 23 0
C (parallel move)
Operation:
Before Execution After Execution
B B
$A8:A86420:A86421
SR SR
$0300 $0329
$D4:543210:543210