FRECPX
Floating-point reciprocal exponent (predicated)
Invert the exponent and zero the fractional part of each active floating-point element of the source vector, and place the results in the corresponding elements of the destination vector. Inactive elements in the destination vector register remain unmodified.
The result of this instruction can be used with FMULX to convert arbitrary elements in mathematical vector space to "unit vectors" or "direction vectors" of length 1.
Green
True
True
True
0
1
1
0
0
1
0
1
0
0
1
1
0
0
1
0
1
FRECPX <Zd>.<T>, <Pg>/M, <Zn>.<T>
if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then UNDEFINED;
if size == '00' then UNDEFINED;
constant integer esize = 8 << UInt(size);
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.
<T>
Is the size specifier,
size
<T>
00
RESERVED
01
H
10
S
11
D
<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 esize;
constant bits(PL) mask = P[g, PL];
constant bits(VL) operand = if AnyActiveElement(mask, esize) then Z[n, VL] else Zeros(VL);
bits(VL) result = Z[d, VL];
for e = 0 to elements-1
if ActivePredicateElement(mask, e, esize) then
constant bits(esize) element = Elem[operand, e, esize];
Elem[result, e, esize] = FPRecpX(element, FPCR);
Z[d, VL] = result;