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.
Green
False
True
0
1
1
0
0
1
0
0
0
1
1
1
0
0
0
0
1
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);
<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.
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;