INSTRUCTION DESCRIPTIONS
A - 146 INSTRUCTION SET DETAILS MOTOROLA
Assembler Syntax: LSR D (parallel move)
Description: Logically shift bits 47–24 of the destination operand D one bit to the right
and store the result in the destination accumulator. Prior to instruction execution, bit 24
of D is shifted into the carry bit C, and a zero is shifted into bit 47 of the destination accu-
mulator D. This instruction is a 24-bit operation. The remaining bits of the destination
operand D are not affected.
Example: :
LSR A1 A1,N4 ;shift A1 one bit to the right, set up N4
:
Explanation of Example: Prior to execution, the 56-bit A accumulator contains the
value $37:444445:828180. The execution of the LSR A instruction shifts the 24-bit value
in the A1 register one bit to the right and stores the result back in the A1 register.
LSR Logical Shift Right LSR
47 24
0C (parallel move)
Operation:
Before Execution After Execution
A A
$37:444445:828180
SR SR
$0300 $0301
$37:222222:828180