movk

Move Keep

MOVK <Wd>, #<imm16> {, lsl #<shift>}

Inserts a 16-bit immediate into a register, keeping other bits unchanged.

Pseudocode Operation

shift_amount ← hw × 16
mask ← 0xFFFF ≪ shift_amount
Wd ← (Wd ∧ ¬mask) ∨ (imm16 ≪ shift_amount)

Example

MOVK w0, #16

Encoding

Binary Layout

0

31

11

30:29

100101

28:23

hw

22:21

imm16

20:5

Rd

4:0

 

Format Data Processing

Opcode 0x72800000

Extension Base

Operands

• Wd
  Destination 32-bit integer register
• imm16
  Imm
• shift
  Shift (0,16)

Related

More in Base

Reference

View in Arm A64 ISA Reference ↗ Arm A64 ISA

Instruction Forms

Encoding	Instruction		ISA		Bit pattern
0x72800000	MOVK <Wd>, #<imm>{, LSL #<shift>}		A64		0 | 11 | 100101 | hw | imm16 | Rd
0xF2800000	MOVK <Xd>, #<imm>{, LSL #<shift>}		A64		1 | 11 | 100101 | hw | imm16 | Rd

Description

Move wide with keep moves an optionally-shifted 16-bit immediate value into a register, keeping other bits unchanged.

Operation

bits(datasize) result;

result = X[d, datasize];
result<pos+15:pos> = imm16;
X[d, datasize] = result;