LSL AX,#1...16
6-135
LSL AX,#1...16 Logical Shift Left
SYNTAX OPTIONS OPCODE OBJMODE RPT CYC
LSL AX,#1…16 1111 1111 100A SHFT X − 1
Operands AX Accumulator high (AH) or accumulator low (AL) register
#1…16 Shift value
Description Perform a logical shift left on the content of the specified AX register (AH or
AL) by the amount given “shift value” field. During the shift, the low order bits
of the AX register are zero filled and the last bit to be shifted out is stored in
the carry bit flag:
0
C
AX
AX
Discard
other bits
Last bit
out
Left 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
; Multiply index register AR0 by 2:
MOV AL,@AR0 ; Load AL with contents of AR0
LSL AL,#1 ; Scale result by 1 (*2)
MOV @AR0,AL ; Store result back in AR0
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