FAMAX

Floating-point absolute maximum (predicated)

Determine the maximum absolute value from active floating-point elements of the second source vector and the corresponding floating-point elements of the first source vector and destructively place the results in the corresponding elements of the first source vector.

The behavior is as follows:

Inactive elements in the destination vector register remain unmodified.

SVE2
(FEAT_FAMINMAX)

313029282726252423222120191817161514131211109876543210
01100101size001110100PgZmZdn

FAMAX <Zdn>.<T>, <Pg>/M, <Zdn>.<T>, <Zm>.<T>

if ((!IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME2)) || !IsFeatureImplemented(FEAT_FAMINMAX)) then UNDEFINED; if size == '00' then UNDEFINED; constant integer esize = 8 << UInt(size); constant integer g = UInt(Pg); constant integer dn = UInt(Zdn); constant integer m = UInt(Zm);

Assembler Symbols

<Zdn>

Is the name of the first source and destination scalable vector register, encoded in the "Zdn" field.

<T>

Is the size specifier, encoded in size:

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.

<Zm>

Is the name of the second source scalable vector register, encoded in the "Zm" field.

Operation

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) operand1 = Z[dn, VL]; constant bits(VL) operand2 = if AnyActiveElement(mask, esize) then Z[m, VL] else Zeros(VL); bits(VL) result; for e = 0 to elements-1 constant bits(esize) element1 = Elem[operand1, e, esize]; if ActivePredicateElement(mask, e, esize) then constant bits(esize) element2 = Elem[operand2, e, esize]; Elem[result, e, esize] = FPAbsMax(element1, element2, FPCR); else Elem[result, e, esize] = element1; Z[dn, VL] = result;

Operational information

This instruction might be immediately preceded in program order by a MOVPRFX instruction. The MOVPRFX must conform to all of the following requirements, otherwise the behavior of the MOVPRFX and this instruction is constrained unpredictable:


Internal version only: aarchmrs v2024-03_relA, pseudocode v2024-03_rel, sve v2024-03_rel ; Build timestamp: 2024-03-26T09:45

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