BF1CVTLT, BF2CVTLT

8-bit floating-point convert to BFloat16 (top)

Convert each odd-numbered 8-bit floating-point element of the source vector to BFloat16 while downscaling the value, and place the results in the overlapping 16-bit elements of the destination vector. BF1CVTLT scales the values by 2-UInt(FPMR.LSCALE[5:0]). BF2CVTLT scales the values by 2-UInt(FPMR.LSCALE2[5:0]).

The 8-bit floating-point encoding format for BF1CVTLT is selected by FPMR.F8S1. The 8-bit floating-point encoding format for BF2CVTLT is selected by FPMR.F8S2.

This instruction is unpredicated.

It has encodings from 2 classes: BF1CVTLT and BF2CVTLT

BF1CVTLT
(FEAT_FP8)

313029282726252423222120191817161514131211109876543210
0110010100001001001110ZnZd
L

BF1CVTLT <Zd>.H, <Zn>.B

if ((!IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME2)) || !IsFeatureImplemented(FEAT_FP8)) then UNDEFINED; constant integer esize = 16; constant integer n = UInt(Zn); constant integer d = UInt(Zd); constant boolean issrc2 = FALSE;

BF2CVTLT
(FEAT_FP8)

313029282726252423222120191817161514131211109876543210
0110010100001001001111ZnZd
L

BF2CVTLT <Zd>.H, <Zn>.B

if ((!IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME2)) || !IsFeatureImplemented(FEAT_FP8)) then UNDEFINED; constant integer esize = 16; constant integer n = UInt(Zn); constant integer d = UInt(Zd); constant boolean issrc2 = TRUE;

Assembler Symbols

<Zd>

Is the name of the destination scalable vector register, encoded in the "Zd" field.

<Zn>

Is the name of the source scalable vector register, encoded in the "Zn" field.

Operation

CheckFPMREnabled(); CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer elements = VL DIV esize; constant bits(VL) operand = Z[n, VL]; bits(VL) result; for e = 0 to elements-1 constant bits(esize DIV 2) element = Elem[operand, 2*e + 1, esize DIV 2]; Elem[result, e, esize] = FP8ConvertBF(element, issrc2, FPCR, FPMR); Z[d, VL] = result;


Internal version only: aarchmrs v2024-03_relA, pseudocode v2024-03_rel, sve v2024-03_rel ; Build timestamp: 2024-03-26T09:45

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