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## FDOT (4-way, vectors)

8-bit floating-point dot product to single-precision

This instruction computes the fused sum-of-products of a group of four 8-bit floating-point values held in each 32-bit element of the first source and second source vectors. The single-precision sum-of-products are scaled by 2-UInt(FPMR.LSCALE), before being destructively added without intermediate rounding to the corresponding single-precision elements of the destination vector.

The 8-bit floating-point encoding format for the elements of the first source vector and the second source vector is selected by FPMR.F8S1 and FPMR.F8S2 respectively.

This instruction is unpredicated.

### SVE2
(FEAT_FP8DOT4)

31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
0 | 1 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | Zm | 1 | 0 | 0 | 0 | 0 | 1 | Zn | Zda

####

FDOT <Zda>.S, <Zn>.B, <Zm>.B

if !HaveSVE2FP8DOT4() then UNDEFINED; constant integer n = UInt(Zn); constant integer m = UInt(Zm); constant integer da = UInt(Zda);

### Assembler Symbols

<Zda> | Is the name of the third source and destination scalable vector register, encoded in the "Zda" field.

<Zn> | Is the name of the first source scalable vector register, encoded in the "Zn" field.

<Zm> | Is the name of the second source scalable vector register, encoded in the "Zm" field.

### Operation

CheckFPMREnabled(); if IsFeatureImplemented(FEAT_FP8DOT4) then CheckSVEEnabled(); else CheckStreamingSVEEnabled(); constant integer VL = CurrentVL; constant integer elements = VL DIV 32; constant bits(VL) operand1 = Z[n, VL]; constant bits(VL) operand2 = Z[m, VL]; constant bits(VL) operand3 = Z[da, VL]; bits(VL) result; for e = 0 to elements-1 constant bits(32) op1 = Elem[operand1, e, 32]; constant bits(32) op2 = Elem[operand2, e, 32]; bits(32) sum = Elem[operand3, e, 32]; sum = FP8DotAddFP(sum, op1, op2, FPCR, FPMR); Elem[result, e, 32] = sum; Z[da, VL] = result;

### Operational information

This instruction might be immediately preceded in program order by a MOVPRFX instruction. The MOVPRFX must conform to all of the following requirements, otherwise the behavior of the MOVPRFX and this instruction is constrained unpredictable:

- The MOVPRFX must be unpredicated.
- The MOVPRFX must specify the same destination register as this instruction.
- The destination register must not refer to architectural register state referenced by any other source operand register of this instruction.

Base Instructions | SIMD&FP Instructions | SVE Instructions | SME Instructions | Index by Encoding | Shared Pseudocode | Proprietary Notice

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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