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FMUL (indexed)

Floating-point multiply by indexed elements.

Multiply all floating-point elements within each 128-bit segment of the first source vector by the specified element in the corresponding second source vector segment. The results are placed in the corresponding elements of the destination vector.

The elements within the second source vector are specified using an immediate index which selects the same element position within each 128-bit vector segment. The index range is from 0 to one less than the number of elements per 128-bit segment, encoded in 1 to 3 bits depending on the size of the element. This instruction is unpredicated.

It has encodings from 3 classes: Half-precision , Single-precision and Double-precision

Half-precision

313029282726252423222120191817161514131211109876543210
011001000i3h1i3lZm001000ZnZd

Half-precision

FMUL <Zd>.H, <Zn>.H, <Zm>.H[<imm>]

if !HaveSVE() then UNDEFINED;
integer esize = 16;
integer index = UInt(i3h:i3l);
integer n = UInt(Zn);
integer m = UInt(Zm);
integer d = UInt(Zd);

Single-precision

313029282726252423222120191817161514131211109876543210
01100100101i2Zm001000ZnZd

Single-precision

FMUL <Zd>.S, <Zn>.S, <Zm>.S[<imm>]

if !HaveSVE() then UNDEFINED;
integer esize = 32;
integer index = UInt(i2);
integer n = UInt(Zn);
integer m = UInt(Zm);
integer d = UInt(Zd);

Double-precision

313029282726252423222120191817161514131211109876543210
01100100111i1Zm001000ZnZd

Double-precision

FMUL <Zd>.D, <Zn>.D, <Zm>.D[<imm>]

if !HaveSVE() then UNDEFINED;
integer esize = 64;
integer index = UInt(i1);
integer n = UInt(Zn);
integer m = UInt(Zm);
integer d = UInt(Zd);

Assembler Symbols

<Zd>

Is the name of the destination scalable vector register, encoded in the "Zd" field.

<Zn>

Is the name of the first source scalable vector register, encoded in the "Zn" field.

<Zm>

For the half-precision and single-precision variant: is the name of the second source scalable vector register Z0-Z7, encoded in the "Zm" field.

For the double-precision variant: is the name of the second source scalable vector register Z0-Z15, encoded in the "Zm" field.

<imm>

For the half-precision variant: is the immediate index, in the range 0 to 7, encoded in the "i3h:i3l" fields.

For the single-precision variant: is the immediate index, in the range 0 to 3, encoded in the "i2" field.

For the double-precision variant: is the immediate index, in the range 0 to 1, encoded in the "i1" field.

Operation

CheckSVEEnabled();
integer elements = VL DIV esize;
integer eltspersegment = 128 DIV esize;
bits(VL) operand1 = Z[n];
bits(VL) operand2 = Z[m];
bits(VL) result;

for e = 0 to elements-1
    integer segmentbase = e - e MOD eltspersegment;
    integer s = segmentbase + index;
    bits(esize) element1 = Elem[operand1, e, esize];
    bits(esize) element2 = Elem[operand2, s, esize];
    Elem[result, e, esize] = FPMul(element1, element2, FPCR);

Z[d] = result;
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