BFDOT (multiple and single vector)

Multi-vector BFloat16 dot product by vector to single-precision

This instruction calculates the dot product of a pair of BF16 values held in the corresponding 32-bit elements of the two or four first source vectors and the second source vector. The single-precision dot product results are destructively added to the corresponding single-precision elements of the ZA single-vector groups.

The single-vector group within each half of or each quarter of the ZA array is selected by the sum of the vector select register and offset, modulo half or quarter the number of ZA array vectors.

The vector group symbol, VGx2 or VGx4, indicates that the ZA operand consists of two or four ZA single-vector groups respectively. The vector group symbol is preferred for disassembly, but optional in assembler source code.

This instruction follows SME2 ZA-targeting BFloat16 numerical behaviors.

This instruction is unpredicated.

It has encodings from 2 classes: Two ZA single-vectors and Four ZA single-vectors

Two ZA single-vectors
(FEAT_SME2)

Decode for this encoding

if !IsFeatureImplemented(FEAT_SME2) then EndOfDecode(Decode_UNDEF); end; let v : integer = UInt('010'::Rv); let n : integer = UInt(Zn); let m : integer = UInt('0'::Zm); let offset : integer = UInt(off3); let nreg : integer{} = 2;

Four ZA single-vectors
(FEAT_SME2)

Decode for this encoding

if !IsFeatureImplemented(FEAT_SME2) then EndOfDecode(Decode_UNDEF); end; let v : integer = UInt('010'::Rv); let n : integer = UInt(Zn); let m : integer = UInt('0'::Zm); let offset : integer = UInt(off3); let nreg : integer{} = 4;