USHLLB

Unsigned shift left long by immediate (bottom)

Shift left by immediate each even-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
010001010tszh0tszlimm3101010ZnZd
UT

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

if !IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME) then UNDEFINED; constant bits(3) tsize = tszh:tszl; if tsize == '000' then UNDEFINED; constant integer esize = 8 << HighestSetBit(tsize); constant integer n = UInt(Zn); constant integer d = UInt(Zd); constant 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 "tszh:tszl:imm3".

Operation

CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer PL = VL DIV 8; constant integer elements = VL DIV (2 * esize); constant bits(VL) operand = Z[n, VL]; bits(VL) result; for e = 0 to elements-1 constant bits(esize) element = Elem[operand, 2*e + 0, esize]; constant integer shifted_value = UInt(element) << shift; Elem[result, e, 2*esize] = shifted_value<2*esize-1:0>; Z[d, VL] = result;

Operational information

If FEAT_SVE2 is implemented or FEAT_SME is implemented, then if PSTATE.DIT is 1:


Internal version only: aarchmrs v2024-03_relA, pseudocode v2024-03_rel, sve v2024-03_rel ; Build timestamp: 2024-03-26T09:45

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