stxsd

Store VSX Scalar Doubleword

stxsd VRS,disp(RA)

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

Details

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

Pseudocode 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.

Example

stxsd v1, disp(RA)

Encoding

Binary Layout
0
0
VRS
6
RA
11
DS
16
2
30
 
Format DS-form
Opcode 0xF4000002
Extension VSX
Registers Altered MSR

Operands

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