vextractuh

Vector Extract Unsigned Halfword

vextractuh RA, vB, UIM

Extracts a halfword from a vector into a GPR.

Encoding

Binary Layout

4

0:5

RA

6:10

UIM

11:15

vB

16:20

589

21:31

 

Format VX-form

Opcode 0x1000024D

Extension VMX (AltiVec)

Operands

• RA
  Target GPR
• vB
  Source Vector
• UIM
  Index

Example

vextractuh r4, vb, uim

Related

More in VMX (AltiVec)

Reference

View in PowerISA v3.1C Specification ↗ OPF Power ISA v3.1C

Description

Extracts an unsigned halfword element from vB at the position specified by UIM and stores the zero-extended 16-bit value into general-purpose register RA. The halfword index (0-7) is provided by the 3-bit immediate UIM. No status flags are affected. This instruction is part of the VMX (AltiVec) extension.

Operation

index ← UIM[1:3]
RA ← (0x0000) || vB[index*16 : index*16+15]

Programming Note

The vextractuh instruction extracts an unsigned halfword from a vector register at a specified index. Ensure the index is within bounds to avoid undefined behavior. This instruction operates in user privilege level and does not generate exceptions for valid indices.