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© 2005-2011 Microchip Technology Inc. DS70157F-page 269
Section 5. Instruction Descriptions
Instruction
Descriptions
5
LSR
Logical Shift Right f
Implemented in: PIC24F PIC24H PIC24E dsPIC30F dsPIC33F dsPIC33E
X X X X X X
Syntax: {label:} LSR{.B} f {,WREG}
Operands: f [0 ... 8191]
Operation: For byte operation:
0 Dest<7>
(f<7:1>) Dest<6:0>
(f<0>) C
For word operation:
0 Dest<15>
(f<15:1>) Dest<14:0>
(f<0>) C
Status Affected: N, Z, C
Encoding:
1101 0101 0BDf ffff ffff ffff
Description: Shift the contents of the file register one bit to the right and place the result
in the destination register. The Least Significant bit of the file register is
shifted into the Carry bit of the STATUS register. Zero is shifted into the
Most Significant bit of the destination register.
The optional WREG operand determines the destination register. If WREG
is specified, the result is stored in WREG. If WREG is not specified, the
result is stored in the file register.
The ‘B’ bit selects byte or word operation (‘0’ for word, ‘1’ for byte).
The ‘D’ bit selects the destination (‘0’ for WREG, ‘1’ for file register).
The ‘f’ bits select the address of the file register.
Note 1: The extension .B in the instruction denotes a byte operation
rather than a word operation. You may use a .W extension to
denote a word operation, but it is not required.
2: The WREG is set to working register W0.
Words: 1
Cycles:
1
(1)
Note 1:
In dsPIC33E and PIC24E devices, the listed cycle count does not apply to read and
read-modify-write operations on non-CPU Special Function Registers. For more
details, see
Note 3
in
Section 3.2.1 “Multi-Cycle Instructions”
.
C
0
Example 1:
LSR.B 0x600 ; Logically shift right (0x600) by one
; (Byte mode)
Before
Instruction
After
Instruction
Data 600 55FF Data 600 557F
SR 0000 SR 0001 (C = 1)

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