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SMULH (unpredicated)

Signed multiply returning high half (unpredicated)

This instruction performs a widening multiplication of signed integer values of all elements of the first source vector by the corresponding elements of the second source vector and places the high half of the result in the corresponding elements of the destination vector. This instruction is unpredicated.

SVE2 class

(FEAT_SVE2 || FEAT_SME)

313029282726252423222120191817161514131211109876543210
00000100size1Zm011010ZnZd
U

Encoding

SMULH <Zd>.<T>, <Zn>.<T>, <Zm>.<T>

Decode

if !IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME) then EndOfDecode(Decode_UNDEF); constant integer esize = 8 << UInt(size); constant integer n = UInt(Zn); constant integer m = UInt(Zm); constant integer d = UInt(Zd); constant boolean unsigned = FALSE;

Assembler Symbols

<Zd>

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

<T>

Is the size specifier, encoded in size:

size <T>
00 B
01 H
10 S
11 D
<Zn>

Is the name of the first source scalable vector register, encoded in the "Zn" 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 elements = VL DIV esize; constant bits(VL) operand1 = Z[n, VL]; constant bits(VL) operand2 = Z[m, VL]; bits(VL) result; for e = 0 to elements-1 constant bits(esize) op1elt = Elem[operand1, e, esize]; constant bits(esize) op2elt = Elem[operand2, e, esize]; constant integer element1 = if unsigned then UInt(op1elt) else SInt(op1elt); constant integer element2 = if unsigned then UInt(op2elt) else SInt(op2elt); constant integer product = (element1 * element2) >> esize; Elem[result, e, esize] = product<esize-1:0>; Z[d, VL] = result;

Operational information

This instruction is a data-independent-time instruction as described in About PSTATE.DIT.


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