FMAX (multiple vectors)
Multi-vector floating-point maximum
Determine the maximum of floating-point elements of the two or four second source vectors and the corresponding floating-point elements of the two or four first source vectors and destructively place the results in the corresponding elements of the two or four first source vectors.
When FPCR.AH is 0, the behavior is as follows:
Negative zero compares less than positive zero.
When FPCR.DN is 0, if either element is a NaN, the result is a quiet NaN.
When FPCR.DN is 1, if either element is a NaN, the result is Default NaN.
When FPCR.AH is 1, the behavior is as follows:
If both elements are zeros, regardless of the sign of either zero, the result is the second element.
If either element is a NaN, regardless of the value of FPCR.DN, the result is the second element.
This instruction follows SME2 floating-point numerical behaviors corresponding to instructions that place their results in one or more SVE Z vectors.
This instruction is unpredicated.
Green
False
SM_1_only
It has encodings from 2 classes:
Two registers
and
Four registers
1
1
0
0
0
0
0
1
!= 00
1
0
1
0
1
1
0
0
0
1
0
0
0
0
FMAX { <Zdn1>.<T>-<Zdn2>.<T> }, { <Zdn1>.<T>-<Zdn2>.<T> }, { <Zm1>.<T>-<Zm2>.<T> }
if !IsFeatureImplemented(FEAT_SME2) then UNDEFINED;
constant integer esize = 8 << UInt(size);
constant integer dn = UInt(Zdn:'0');
constant integer m = UInt(Zm:'0');
constant integer nreg = 2;
1
1
0
0
0
0
0
1
!= 00
1
0
0
1
0
1
1
1
0
0
1
0
0
0
0
0
FMAX { <Zdn1>.<T>-<Zdn4>.<T> }, { <Zdn1>.<T>-<Zdn4>.<T> }, { <Zm1>.<T>-<Zm4>.<T> }
if !IsFeatureImplemented(FEAT_SME2) then UNDEFINED;
constant integer esize = 8 << UInt(size);
constant integer dn = UInt(Zdn:'00');
constant integer m = UInt(Zm:'00');
constant integer nreg = 4;
<Zdn1>
For the two registers variant: is the name of the first scalable vector register of the destination and first source multi-vector group, encoded as "Zdn" times 2.
<Zdn1>
For the four registers variant: is the name of the first scalable vector register of the destination and first source multi-vector group, encoded as "Zdn" times 4.
<T>
Is the size specifier,
<Zdn4>
Is the name of the fourth scalable vector register of the destination and first source multi-vector group, encoded as "Zdn" times 4 plus 3.
<Zdn2>
Is the name of the second scalable vector register of the destination and first source multi-vector group, encoded as "Zdn" times 2 plus 1.
<Zm1>
For the two registers variant: is the name of the first scalable vector register of the second source multi-vector group, encoded as "Zm" times 2.
<Zm1>
For the four registers variant: is the name of the first scalable vector register of the second source multi-vector group, encoded as "Zm" times 4.
<Zm4>
Is the name of the fourth scalable vector register of the second source multi-vector group, encoded as "Zm" times 4 plus 3.
<Zm2>
Is the name of the second scalable vector register of the second source multi-vector group, encoded as "Zm" times 2 plus 1.
CheckStreamingSVEEnabled();
constant integer VL = CurrentVL;
constant integer elements = VL DIV esize;
array [0..3] of bits(VL) results;
for r = 0 to nreg-1
constant bits(VL) operand1 = Z[dn+r, VL];
constant bits(VL) operand2 = Z[m+r, VL];
for e = 0 to elements-1
constant bits(esize) element1 = Elem[operand1, e, esize];
constant bits(esize) element2 = Elem[operand2, e, esize];
Elem[results[r], e, esize] = FPMax(element1, element2, FPCR);
for r = 0 to nreg-1
Z[dn+r, VL] = results[r];