BFMLALT (vectors)
BFloat16 floating-point multiply-add long to single-precision (top)
This BFloat16 floating-point multiply-add long instruction widens the odd-numbered BFloat16 elements in the first source vector and the corresponding elements in the second source vector to single-precision format and then destructively multiplies and adds these values without intermediate rounding to the single-precision elements of the destination vector that overlap with the corresponding BFloat16 elements in the source vectors. This instruction is unpredicated.
ID_AA64ZFR0_EL1.BF16 indicates whether this instruction is implemented.
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BFMLALT <Zda>.S, <Zn>.H, <Zm>.H
if ((!IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME)) ||
!IsFeatureImplemented(FEAT_BF16)) then UNDEFINED;
constant integer n = UInt(Zn);
constant integer m = UInt(Zm);
constant integer da = UInt(Zda);
constant boolean op1_neg = FALSE;
<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.
CheckSVEEnabled();
constant integer VL = CurrentVL;
constant integer PL = VL DIV 8;
constant integer elements = VL DIV 32;
constant bits(VL) op1 = Z[n, VL];
constant bits(VL) op2 = Z[m, VL];
constant bits(VL) op3 = Z[da, VL];
bits(VL) result;
for e = 0 to elements-1
constant bits(16) elem1 = (if op1_neg then BFNeg(Elem[op1, 2*e + 1, 16])
else Elem[op1, 2*e + 1, 16]);
constant bits(16) elem2 = Elem[op2, 2*e + 1, 16];
constant bits(32) elem3 = Elem[op3, e, 32];
Elem[result, e, 32] = BFMulAddH(elem3, elem1, elem2, FPCR);
Z[da, VL] = result;