BFMAXNM (multiple vectors)

Multi-vector BFloat16 floating-point maximum number

Determine the maximum number value of BFloat16 elements of the two or four second source vectors and the corresponding BFloat16 elements of the two or four first source vectors and destructively place the results in the corresponding elements of the two or four first source vectors.

Regardless of the value of FPCR.AH, the behavior is as follows:

This instruction follows SME2 non-widening BFloat16 numerical behaviors corresponding to instructions that place their results in two or four SVE Z vectors.

This instruction is unpredicated.

ID_AA64SMFR0_EL1.B16B16 indicates whether this instruction is implemented.

It has encodings from 2 classes: Two registers and Four registers

Two registers
(FEAT_SVE_B16B16)

313029282726252423222120191817161514131211109876543210
11000001001Zm010110001001Zdn0
size<1>size<0>

BFMAXNM { <Zdn1>.H-<Zdn2>.H }, { <Zdn1>.H-<Zdn2>.H }, { <Zm1>.H-<Zm2>.H }

if !IsFeatureImplemented(FEAT_SME2) || !IsFeatureImplemented(FEAT_SVE_B16B16) then UNDEFINED; constant integer dn = UInt(Zdn:'0'); constant integer m = UInt(Zm:'0'); constant integer nreg = 2;

Four registers
(FEAT_SVE_B16B16)

313029282726252423222120191817161514131211109876543210
11000001001Zm0010111001001Zdn00
size<1>size<0>

BFMAXNM { <Zdn1>.H-<Zdn4>.H }, { <Zdn1>.H-<Zdn4>.H }, { <Zm1>.H-<Zm4>.H }

if !IsFeatureImplemented(FEAT_SME2) || !IsFeatureImplemented(FEAT_SVE_B16B16) then UNDEFINED; constant integer dn = UInt(Zdn:'00'); constant integer m = UInt(Zm:'00'); constant integer nreg = 4;

Assembler Symbols

<Zdn1>

For the two registers variant: is the name of the first scalable vector register of the destination and first source multi-vector group, encoded as "Zdn" times 2.

For the four registers variant: is the name of the first scalable vector register of the destination and first source multi-vector group, encoded as "Zdn" times 4.

<Zdn4>

Is the name of the fourth scalable vector register of the destination and first source multi-vector group, encoded as "Zdn" times 4 plus 3.

<Zdn2>

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

<Zm1>

For the two registers variant: is the name of the first scalable vector register of the second source multi-vector group, encoded as "Zm" times 2.

For the four registers variant: is the name of the first scalable vector register of the second source multi-vector group, encoded as "Zm" times 4.

<Zm4>

Is the name of the fourth scalable vector register of the second source multi-vector group, encoded as "Zm" times 4 plus 3.

<Zm2>

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

Operation

CheckStreamingSVEEnabled(); constant integer VL = CurrentVL; constant integer elements = VL DIV 16; array [0..3] of bits(VL) results; for r = 0 to nreg-1 constant bits(VL) operand1 = Z[dn+r, VL]; constant bits(VL) operand2 = Z[m+r, VL]; for e = 0 to elements-1 constant bits(16) element1 = Elem[operand1, e, 16]; constant bits(16) element2 = Elem[operand2, e, 16]; Elem[results[r], e, 16] = BFMaxNum(element1, element2, FPCR); for r = 0 to nreg-1 Z[dn+r, VL] = results[r];


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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