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DUP (indexed)

Broadcast indexed element to vector (unpredicated).

Unconditionally broadcast the indexed source vector element into each element of the destination vector. This instruction is unpredicated.

The immediate element index is in the range of 0 to 63 (bytes), 31 (halfwords), 15 (words), 7 (doublewords) or 3 (quadwords). Selecting an element beyond the accessible vector length causes the destination vector to be set to zero.

This instruction is used by the alias MOV (SIMD&FP scalar, unpredicated).

313029282726252423222120191817161514131211109876543210
00000101imm21tsz001000ZnZd

SVE

DUP <Zd>.<T>, <Zn>.<T>[<imm>]

if !HaveSVE() then UNDEFINED;
bits(7) imm = imm2:tsz;
case tsz of
    when '00000' UNDEFINED;
    when '10000' esize = 128; index = UInt(imm<6:5>);
    when 'x1000' esize = 64;  index = UInt(imm<6:4>);
    when 'xx100' esize = 32;  index = UInt(imm<6:3>);
    when 'xxx10' esize = 16;  index = UInt(imm<6:2>);
    when 'xxxx1' esize = 8;   index = UInt(imm<6:1>);
integer n = UInt(Zn);
integer d = UInt(Zd);

Assembler Symbols

<Zd>

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

<T> Is the size specifier, encoded in tsz:
tsz <T>
00000 RESERVED
xxxx1 B
xxx10 H
xx100 S
x1000 D
10000 Q
<Zn>

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

<imm>

Is the immediate index, in the range 0 to one less than the number of elements in 512 bits, encoded in "imm2:tsz".

Alias Conditions

AliasIs preferred when
MOV (SIMD&FP scalar, unpredicated)BitCount(imm2:tsz) == 1
MOV (SIMD&FP scalar, unpredicated)BitCount(imm2:tsz) > 1

Operation

CheckSVEEnabled();
integer elements = VL DIV esize;
bits(VL) operand1 = Z[n];
bits(VL) result;
bits(esize) element;

if index >= elements then
    element = Zeros();
else
    element = Elem[operand1, index, esize];
result = Replicate(element);

Z[d] = result;

Operational information

If PSTATE.DIT is 1:

  • The execution time of this instruction is independent of:
    • The values of the data supplied in any of its registers.
    • The values of the NZCV flags.
  • The response of this instruction to asynchronous exceptions does not vary based on:
    • The values of the data supplied in any of its registers.
    • The values of the NZCV flags.
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