FCVTNB

Single-precision convert, narrow and interleave to 8-bit floating-point (bottom)

Convert each single-precision element of the group of two source vectors to 8-bit floating-point while scaling the value by 2SInt(FPMR.NSCALE), and place the two-way interleaved results in the corresponding even-numbered 8-bit elements of the destination vector, zeroing the odd-numbered elements. The 8-bit floating-point encoding format is selected by FPMR.F8D.

This instruction is unpredicated.

SVE2
(FEAT_FP8)

313029282726252423222120191817161514131211109876543210
0110010100001010001101Zn0Zd
T

FCVTNB <Zd>.B, { <Zn1>.S-<Zn2>.S }

if (!HaveSVE2() && !HaveSME2()) || !IsFeatureImplemented(FEAT_FP8) then UNDEFINED; integer n = UInt(Zn:'0'); integer d = UInt(Zd);

Assembler Symbols

<Zd>

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

<Zn1>

Is the name of the first scalable vector register of the source multi-vector group, encoded as "Zn" times 2.

<Zn2>

Is the name of the second scalable vector register of the source multi-vector group, encoded as "Zn" times 2 plus 1.

Operation

CheckFPMREnabled(); CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer elements = VL DIV 32; bits(VL) result; bits(VL) operand1 = Z[n+0, VL]; bits(VL) operand2 = Z[n+1, VL]; for e = 0 to elements-1 bits(32) element1 = Elem[operand1, e, 32]; bits(32) element2 = Elem[operand2, e, 32]; bits(8) res1 = FPConvertFP8(element1, FPCR, FPMR, 8); bits(8) res2 = FPConvertFP8(element2, FPCR, FPMR, 8); Elem[result, 2*e + 0, 16] = ZeroExtend(res1, 16); Elem[result, 2*e + 1, 16] = ZeroExtend(res2, 16); Z[d, VL] = result;


Internal version only: aarchmrs v2023-12_rel, pseudocode v2023-12_rel, sve v2023-12_rel ; Build timestamp: 2023-12-15T16:46

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