BFCVTNT
Floating-point down convert and narrow to BFloat16 (top, predicated)
Convert to BFloat16 from single-precision in each active floating-point element of the source vector, and place the results in the odd-numbered 16-bit elements of the destination vector, leaving the even-numbered elements unchanged. Inactive elements in the destination vector register remain unmodified.
ID_AA64ZFR0_EL1.BF16 indicates whether this instruction is implemented.
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BFCVTNT <Zd>.H, <Pg>/M, <Zn>.S
if ((!IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME)) ||
!IsFeatureImplemented(FEAT_BF16)) then UNDEFINED;
constant integer g = UInt(Pg);
constant integer n = UInt(Zn);
constant integer d = UInt(Zd);
<Zd>
Is the name of the destination scalable vector register, encoded in the "Zd" field.
<Pg>
Is the name of the governing scalable predicate register P0-P7, encoded in the "Pg" field.
<Zn>
Is the name of the source scalable vector register, encoded in the "Zn" field.
CheckSVEEnabled();
constant integer VL = CurrentVL;
constant integer PL = VL DIV 8;
constant integer elements = VL DIV 32;
constant bits(PL) mask = P[g, PL];
constant bits(VL) operand = if AnyActiveElement(mask, 32) then Z[n, VL] else Zeros(VL);
bits(VL) result = Z[d, VL];
for e = 0 to elements-1
if ActivePredicateElement(mask, e, 32) then
constant bits(32) element = Elem[operand, e, 32];
Elem[result, 2*e+1, 16] = FPConvertBF(element, FPCR);
Z[d, VL] = result;