xxblendvh

VSX Vector Blend Variable Halfword

xxblendvh XT, XA, XB, XC

Selects halfwords from XA or XB based on the MSB of halfwords in XC.

Encoding

Binary Layout
60
0:5
XT
6:10
XA
11:15
XB
16:20
XC
21:25
34
26:31
 
Format XX4-form
Opcode 0x0500000084000010
Extension VSX

Operands

  • XT
    Target
  • XA
    Src A
  • XB
    Src B
  • XC
    Control
  • VRT
    Target VSX Register
  • VRA
    Source VSX Register
  • VRB
    Source VSX Register

Example

xxblendvh vs1, vs2, vs3, vs4

Registers Altered

MSR

Related

More in VSX

Reference

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

Description

For xxblendvh, the contents of each halfword in the target vector are selected from either the first or second source vector based on the corresponding bit in the control vector.

Operation

if MSR.VSX=0 then VSX_Unavailable()
do i = 0 to 7
    if VSR[32×CX+C].hword[i].bit[0]=0 then
        VSR[32×TX+T].hword[i] ←VSR[32×AX+A].hword[i]
    else
        VSR[32×TX+T].hword[i] ←VSR[32×BX+B].hword[i]
end

Programming Note

Ensure VSX is enabled by checking and setting the appropriate bit in the MSR register. This instruction blends halfwords from two source vectors into a target vector based on a control vector's bits. Be cautious of alignment requirements for vector registers to avoid undefined behavior.