FMAXNMP

Floating-point maximum number pairwise

Compute the maximum value of each pair of adjacent floating-point elements within each source vector, and interleave the results from corresponding lanes. The interleaved result values are destructively placed in the first source vector.

Regardless of the value of FPCR.AH, the behavior is as follows for each pairwise operation:

  • Negative zero compares less than positive zero.
  • If one element is numeric and the other is a quiet NaN, the result is the numeric value.
  • When FPCR.DN is 0, if either element is a signaling NaN or if both elements are NaNs, the result is a quiet NaN.
  • When FPCR.DN is 1, if either element is a signaling NaN or if both elements are NaNs, the result is Default NaN.

    • Encoding: SVE2

    Variants: FEAT_SVE2 || FEAT_SME (FEAT_SVE2 || FEAT_SME)

    313029282726252423222120191817161514131211109876543210
    01100100010100100
    sizeopcPgZmZdn

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

    Decoding algorithm

    if !IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME) then
    EndOfDecode(Decode_UNDEF);
if size == '00' then EndOfDecode(Decode_UNDEF);
constant integer esize = 8 << UInt(size);
constant integer g = UInt(Pg);
constant integer m = UInt(Zm);
constant integer dn = UInt(Zdn);

    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 = Z[dn, VL];
bits(esize) element1;
bits(esize) element2;

for e = 0 to elements-1
    if ActivePredicateElement(mask, e, esize) then
        if IsEven(e) then
            element1 = Elem[operand1, e + 0, esize];
            element2 = Elem[operand1, e + 1, esize];
        else
            element1 = Elem[operand2, e - 1, esize];
            element2 = Elem[operand2, e + 0, esize];
        Elem[result, e, esize] = FPMaxNum(element1, element2, FPCR);

Z[dn, VL] = result;

    Explanations

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

    Operational Notes

    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: