sxtb

Sign Extend Byte

SXTB <Wd>, <Wn>

Extracts the lowest 8 bits and sign-extends to 32 bits (Alias for SBFM).

Pseudocode Operation

Wd ← SignExtend(Wn[7:0], 32)

Example

SXTB w0, w1

Encoding

Binary Layout

0

31

00

30:29

100110

28:23

0

22

000000

21:16

000111

15:10

Rn

9:5

Rd

4:0

 

Format Bitfield

Opcode 0x13001C00

Extension Base

Operands

• Wd
  Destination 32-bit integer register
• Wn
  First source / base 32-bit integer register

Related

Other forms of sxtb

• sxtb Signed Extend Byte (Thumb)
• sxtb Signed Extend Byte (A32)

Across architectures

Sign Extend Byte : how x86, ARM, RISC-V, and PowerISA each do this.

More in Base

Reference

View in Arm A64 ISA Reference ↗ Arm A64 ISA

Instruction Forms

Encoding	Instruction		ISA		Bit pattern
0x13001C00	SXTB <Wd>, <Wn>		A64		0 | 00 | 100110 | 0 | 000000 | 000111 | Rn | Rd
0x93401C00	SXTB <Xd>, <Wn>		A64		1 | 00 | 100110 | 1 | 000000 | 000111 | Rn | Rd
0x0410A000	SXTB <Zd>.<T>, <Pg>/M, <Zn>.<T>		A64		00000100 | size | 010 | 00 | 0 | 101 | Pg | Zn | Zd

Description

Signed Extend Byte extracts an 8-bit value from a register, sign-extends it to the size of the register, and writes the result to the destination register.