xvrspi

VSX Vector Round to Single-Precision Integer

xvrspi XT,XB

Rounds each element of a vector from single-precision floating-point format to an integer using round to Nearest Away.

Encoding

Binary Layout

6:10

11:15

16:20

21:31

Format XX2-form

Opcode 0xF0000224

Extension VSX

Operands

XT
Target Vector-Specific Register
XB
Source Vector-Specific Register

Example

xvrspi vs1, vs3

Registers Altered

FPSCR, VXSNAN

Reference

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

Description

For xvrspi, each element of the source vector VSR[XB] is rounded to an integer using the rounding mode Round to Nearest Away. The result is placed into the corresponding element of the target vector VSR[XT]. If a Signalling NaN is encountered, it is converted to a Quiet NaN and VXSNAN is set to 1.

Operation

if MSR.VSX=0 then VSX_Unavailable()

ex_flag ←0b0

do i = 0 to 3
    reset_xflags()
    src ←bfp_CONVERT_FROM_BFP32(VSR[32×BX+B].word[i])
    rnd ←bfp_ROUND_TO_INTEGER(0b100, src)
    vresult.word[i] ←bfp32_CONVERT_FROM_BFP(rnd)

    if vxsnan_flag=1 then SetFX(FPSCR.VXSNAN)
    ex_flag ←ex_flag | (FPSCR.VE & vxsnan_flag)
end

if ex_flag=0 then VSR[32×TX+T] ←vresult

Programming Note

The xvrspi instruction rounds each element of the source vector to an integer using the Round to Nearest Away mode. It handles Signalling NaNs by converting them to Quiet NaNs and setting VXSNAN in the FPSCR register. Ensure that VSX is enabled (MSR.VSX=1) before using this instruction, as attempting to use it when VSX is unavailable will result in an exception.