Unsigned shift left long by immediate (top)
This instruction shifts left by immediate each odd-numbered unsigned element of the source vector, and places 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.
| 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| 0 | 1 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | tszh | 0 | tszl | imm3 | 1 | 0 | 1 | 0 | 1 | 1 | Zn | Zd | |||||||||||
| U | T | ||||||||||||||||||||||||||||||
if !IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME) then EndOfDecode(Decode_UNDEF); end; let tsize : bits(3) = tszh::tszl; if tsize == '000' then EndOfDecode(Decode_UNDEF); end; let esize : integer{} = 8 << HighestSetBitNZ(tsize); let n : integer = UInt(Zn); let d : integer = UInt(Zd); let shift : integer = UInt(tsize::imm3) - esize;
| <Zd> |
Is the name of the destination scalable vector register, encoded in the "Zd" field. |
| <T> |
Is the size specifier,
encoded in
|
| <Zn> |
Is the name of the source scalable vector register, encoded in the "Zn" field. |
| <Tb> |
Is the size specifier,
encoded in
|
| <const> |
Is the immediate shift amount, in the range 0 to number of bits per element minus 1, encoded in "tszh:tszl:imm3". |
CheckSVEEnabled(); let VL : integer{} = CurrentVL(); let elements : integer = VL DIV (2 * esize); let operand : bits(VL) = Z{}(n); var result : bits(VL); for e = 0 to elements-1 do let element : bits(esize) = operand[(2*e + 1)*:esize]; let shifted_value : integer = UInt(element) << shift; result[e*:(2*esize)] = shifted_value[2*esize-1:0]; end; Z{VL}(d) = result;
This instruction is a data-independent-time instruction as described in About PSTATE.DIT.
2025-09_diff_tag 2025-11-28 16:29:05
Copyright © 2010-2025 Arm Limited or its affiliates. All rights reserved. This document is Non-Confidential.