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UQSHRNB

Unsigned saturating shift right narrow by immediate (bottom).

Shift each unsigned integer value in the source vector elements right by an immediate value, and place the truncated results in the even-numbered half-width destination elements, while setting the odd-numbered elements to zero. Each result element is saturated to the half-width N-bit element's unsigned integer range 0 to (2N)-1. The immediate shift amount is an unsigned value in the range 1 to number of bits per element. This instruction is unpredicated.

313029282726252423222120191817161514131211109876543210
010001010tszh1tszlimm3001100ZnZd

SVE2

UQSHRNB <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 = (2 * esize) - UInt(tsize:imm3);

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 B
0 1x H
1 xx S
<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 H
0 1x S
1 xx D
<const>

Is the immediate shift amount, in the range 1 to number of bits per element, 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(2*esize) element = Elem[operand, e, 2*esize];
    integer res = UInt(element) >> shift;
    Elem[result, 2*e + 0, esize] = UnsignedSat(res, esize);
    Elem[result, 2*e + 1, esize] = Zeros();

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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