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## LSR (immediate)

Logical Shift Right (immediate) shifts a register value right by an immediate number of bits, shifting in zeros, and writes the result to the destination register.

This is an alias of UBFM. This means:

- The encodings in this description are named to match the encodings of UBFM.
- The description of UBFM gives the operational pseudocode, any constrained unpredictable behavior, and any operational information for this instruction.

31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
sf | 1 | 0 | 1 | 0 | 0 | 1 | 1 | 0 | N | immr | x | 1 | 1 | 1 | 1 | 1 | Rn | Rd
| opc |  |  |  | imms |  |

#### 32-bit (sf == 0 && N == 0 && imms == 011111)

LSR <Wd>, <Wn>, #<shift>

is equivalent to

UBFM <Wd>, <Wn>, #<shift>, #31

and is always the preferred disassembly.

#### 64-bit (sf == 1 && N == 1 && imms == 111111)

LSR <Xd>, <Xn>, #<shift>

is equivalent to

UBFM <Xd>, <Xn>, #<shift>, #63

and is always the preferred disassembly.

### Assembler Symbols

<Wd> | Is the 32-bit name of the general-purpose destination register, encoded in the "Rd" field.

<Wn> | Is the 32-bit name of the general-purpose source register, encoded in the "Rn" field.

<Xd> | Is the 64-bit name of the general-purpose destination register, encoded in the "Rd" field.

<Xn> | Is the 64-bit name of the general-purpose source register, encoded in the "Rn" field.

<shift> | For the 32-bit variant: is the shift amount, in the range 0 to 31, encoded in the "immr" field.
| For the 64-bit variant: is the shift amount, in the range 0 to 63, encoded in the "immr" field.

### Operation

The description of UBFM gives the operational pseudocode for this instruction.

### Operational information

If PSTATE.DIT is 1:

- The execution time of this instruction is independent of:
  - The values of the data supplied in any of its registers.
  - The values of the NZCV flags.
- The response of this instruction to asynchronous exceptions does not vary based on:
  - The values of the data supplied in any of its registers.
  - The values of the NZCV flags.

Base Instructions | SIMD&FP Instructions | SVE Instructions | SME Instructions | Index by Encoding | Shared Pseudocode | Proprietary Notice

Internal version only: isa v33.74, AdvSIMD v29.23, pseudocode v2023-09_rel, sve v2023-09_rc3 ; Build timestamp: 2023-09-27T17:06

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