FDOT (half-precision to single-precision, by element)

Half-precision dot product to single-precision (vector, by element)

This instruction calculates the fused sum-of-products of a pair of half-precision values held in each 32-bit element of the first source vector and a pair of half-precision values held in an indexed 32-bit element of the second source vector, without intermediate rounding, and then destructively adds the single-precision sum-of-products to the corresponding single-precision element of the destination vector.

Advanced SIMD
(FEAT_F16F32DOT)

313029282726252423222120191817161514131211109876543210
0Q00111101LMRm1001H0RnRd
Usizeopcode

Encoding

FDOT <Vd>.<Ta>, <Vn>.<Tb>, <Vm>.2H[<index>]

Decode for this encoding

if !IsFeatureImplemented(FEAT_F16F32DOT) then EndOfDecode(Decode_UNDEF); end; let n : integer = UInt(Rn); let m : integer = UInt(M::Rm); let d : integer = UInt(Rd); let i : integer = UInt(H::L); let datasize : integer{} = 64 << UInt(Q); let elements : integer = datasize DIV 32;

Assembler Symbols

<Vd>

Is the name of the SIMD&FP destination register, encoded in the "Rd" field.

<Ta>

Is an arrangement specifier, encoded in Q:

Q <Ta>
0 2S
1 4S
<Vn>

Is the name of the first SIMD&FP source register, encoded in the "Rn" field.

<Tb>

Is an arrangement specifier, encoded in Q:

Q <Tb>
0 4H
1 8H
<Vm>

Is the name of the second SIMD&FP source register, encoded in the "M:Rm" fields.

<index>

Is the immediate index of a pair of 16-bit elements in the range 0 to 3, encoded in the "H:L" fields.


2025-12_rel 2025-12-10 16:41:45

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