xsiexpdp

VSX Scalar Insert Exponent Double-Precision

xsiexpdp XT, XA, XB

Inserts exponent from one double into another.

Encoding

Binary Layout

60

0:5

XT

6:10

XA

11:15

XB

16:20

219

21:31

 

Format XX3-form

Opcode 0xF000072C

Extension VSX

Operands

• XT
  Target
• XA
  Significand
• XB
  Exponent
• RA
  Source General Purpose Register
• RB
  Source General Purpose Register

Example

xsiexpdp vs1, vs2, vs3

Registers Altered

VSR[XT]

Related

More in VSX

Reference

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

Description

Inserts the exponent bits from XB (bits 0-10) into the exponent field of the significand in XA, placing the result in XT. This operation constructs a double-precision floating-point value by combining a significand with a new exponent. Requires VSX support.

Operation

XT ← (XA[0:51] || XB[0:10])

Programming Note

This instruction can be used to produce a single-precision result. 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, as is required by this version of the architecture.