vrefp

Vector Reciprocal Estimate Floating-Point VX-form

vrefp VRT,VRB

Estimates the reciprocal of single-precision floating-point elements in a vector.

Encoding

Binary Layout

4

0:5

VRT

6:10

VRB

11:31

 

Format VX-form

Opcode 0x1000010A

Extension VMX (AltiVec)

Operands

• VRT
  Target Vector Register
• VRB
  Source Vector Register

Example

vrefp v1, v3

Registers Altered

MSR

Related

More in VMX (AltiVec)

Reference

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

Description

For vrefp, the single-precision floating-point estimate of the reciprocal of each element in VSR[VRB+32] is placed into corresponding elements in VSR[VRT+32].

Operation

if MSR.VEC=0 then
    Vector_Unavailable()
do i = 0 to 3
    src ← VSR[VRB+32].word[i]
    VSR[VRT+32].word[i] ← bfp32_RECIPROCAL_ESTIMATE(src)
end

Programming Note

The vrefp instruction estimates the reciprocal of each single-precision floating-point element in the source vector and stores it in the destination vector. Ensure that the Vector Facility is enabled by checking and setting the VEC bit in the MSR register. This instruction operates on vectors containing 32-bit floating-point numbers, and it does not raise exceptions for invalid operations like division by zero; instead, it returns a NaN or infinity as appropriate.