LSR AX,#1...16
6-140
LSR AX,#1...16 Logical Shift Right
SYNTAX OPTIONS OPCODE OBJMODE RPT CYC
LSR AX,#1…16 1111 1111 110A SHFT X − 1
Operands AX Accumulator high (AH) or accumulator low (AL) register
#1…16 Shift value
Description Perform a logical right shift on the content of the specified AX register by the
amount given by the “shift value” field. During the shift, the high order bits of
the AX register are zero filled and the last bit to be shifted out is stored in the
carry flag bit:
0
C
AX
AX
Discard
other bits
Last bit out
Right shift
(Immediate value)
Flags and
Modes
N
After the shift, if bit 15 of AX is 1 then the negative flag bit is set; otherwise it is
cleared.
Z
After the shift, if AX is 0, then the Z bit is set, otherwise it is cleared.
C
The last bit to be shifted out of AH or AL is stored in C.
Repeat This instruction is not repeatable. If this instruction follows the RPT
instruction, it resets the repeat counter (RPTC) and executes only once.
Example
; Divide index register AR0 by 2:
MOV AL,@AR0 ; Load AL with contents of AR0
LSR AL,#1 ; Scale result by 1 (/2)
MOV @AR0,AL ; Store result back in AR0
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