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USHLLT

Unsigned shift left long by immediate (top).

Shift left by immediate each odd-numbered unsigned element of the source vector, and place the results in the overlapping double-width elements of the destination vector. The immediate shift amount is an unsigned value in the range 0 to number of bits per element minus 1. This instruction is unpredicated.

313029282726252423222120191817161514131211109876543210
010001010tszh0tszlimm3101011ZnZd

SVE2

USHLLT <Zd>.<T>, <Zn>.<Tb>, #<const>

if !HaveSVE2() then UNDEFINED;
bits(3) tsize = tszh:tszl;
case tsize of
    when '000' UNDEFINED;
    when '001' esize = 8;
    when '01x' esize = 16;
    when '1xx' esize = 32;
integer n = UInt(Zn);
integer d = UInt(Zd);
integer shift = UInt(tsize:imm3) - esize;

Assembler Symbols

<Zd>

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

<T> Is the size specifier, encoded in tszh:tszl:
tszh tszl <T>
0 00 RESERVED
0 01 H
0 1x S
1 xx D
<Zn>

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

<Tb> Is the size specifier, encoded in tszh:tszl:
tszh tszl <Tb>
0 00 RESERVED
0 01 B
0 1x H
1 xx S
<const>

Is the immediate shift amount, in the range 0 to number of bits per element minus 1, encoded in "tsz:imm3".

Operation

CheckSVEEnabled();
integer elements = VL DIV (2 * esize);
bits(VL) operand = Z[n];
bits(VL) result;

for e = 0 to elements-1
    bits(esize) element = Elem[operand, 2*e + 1, esize];
    integer shifted_value = UInt(element) << shift;
    Elem[result, e, 2*esize] = shifted_value<2*esize-1:0>;

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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