stxsd

Store VSX Scalar Doubleword

stxsd VRS,disp(RA)

Stores the contents of doubleword element 0 of VSR[XS] to memory.

Encoding

Binary Layout

0

0:5

VRS

6:10

RA

11:15

DS

16:29

2

30:31

 

Format DS-form

Opcode 0xF4000002

Extension VSX

Operands

• VRS
  Vector-Scalar Register
• RA
  Source General Purpose Register
• disp
  Displacement value

Example

stxsd v1, disp(RA)

Registers Altered

MSR

Related

More in VSX

Reference

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

Description

The instruction stores the contents of doubleword element 0 of VSR[XS] to memory at the effective address (EA) calculated from RA and DS.

Operation

if MSR.VEC=0 then Vector_Unavailable()
EA ← (RA|0) + EXTS64(DS||0b00)
MEM(EA,8) ← VSR[VRS+32].dword[0]

Programming Note

The stxsd instruction stores the first doubleword of a VSX register to memory. Ensure that the Vector Facility is enabled by checking and setting MSR.VEC if necessary. The EA must be 8-byte aligned for optimal performance, though unaligned accesses are supported with potential performance penalties.