xsresp

VSX Scalar Reciprocal Estimate Single-Precision

xsresp XT,XB

Estimates the reciprocal of a single-precision floating-point value.

Details

Computes an estimate of the reciprocal (1/XB) for a single-precision floating-point scalar value, placing the result in XT. The estimate is accurate to about 7 bits of precision. This instruction requires VSX support and may update FPSCR exception flags if the source is invalid or zero.

Pseudocode Operation

XT[32:63] ← reciprocal_estimate(XB[32:63])
FPSCR ← update_exception_flags(FPSCR, result)

Programming Note

Previous versions of the architecture allowed the contents of doubleword 1 of the result register to be undefined. However, all processors that support this instruction write 0s into doubleword 1 of the result register.

Example

xsresp vs1, vs3

Encoding

Binary Layout
T
6
B
11
26
16
BX
21
TX
30
 
Format XX2-form
Opcode 0xF0000068
Extension VSX
Registers Altered FPSCR, VXSNAN

Operands

  • XT
    Target Vector-Scalar Register
  • XB
    Source Vector-Scalar Register