stxvrbx

Store VSX Vector Rightmost Byte Indexed X-form

stxvrbx XS,RA,RB

Stores the rightmost byte of a VSX vector element to memory.

Details

The contents of byte element 15 of VSR[XS] are placed into storage at address EA, which is the sum of GPR[RA] and GPR[RB]. If RA=0, EA is just GPR[RB].

Pseudocode Operation

if MSR.VSX=0 then VSX_Unavailable()
EA = ((RA=0) ? 0 : GPR[RA]) + GPR[RB];
MEM(EA,1) = VSR[32×SX+S].byte[15];

Programming Note

This instruction stores the rightmost byte of a VSX vector register into memory. Ensure that the VSX facility is enabled (MSR.VSX=1) to avoid an exception. The effective address (EA) is calculated by adding GPR[RA] and GPR[RB], unless RA is 0, in which case EA is just GPR[RB]. Be cautious of alignment; while not strictly required for a single byte, proper alignment can improve performance.

Example

stxvrbx vs1, r4, r5

Encoding

Binary Layout
0
0
S
6
RA
11
RB
16
16
21
SX
26
21
31
31
 
Format X-form
Opcode 0x7C00011A
Extension VSX

Operands

  • XS
    VSX Vector Register
  • RA
    General Purpose Register (Base Address)
  • RB
    General Purpose Register (Index)