Lookup table read with 2-bit indices
This instruction copies indexed 8-bit or 16-bit elements from the low 128 bits of the table vector to the destination vector using packed 2-bit indices from a segment of the source vector. A segment corresponds to a portion of the source vector that is consumed in order to fill the destination vector. The segment is selected by the vector segment index. This instruction is unpredicated.
It has encodings from 2 classes: Byte and Halfword
| 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 | i2 | 1 | Zm | 1 | 0 | 1 | 1 | 0 | 0 | Zn | Zd | |||||||||||||
if ((!IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME2)) || !IsFeatureImplemented(FEAT_LUT)) then UNDEFINED; constant integer isize = 2; constant integer esize = 8; constant integer m = UInt(Zm); constant integer n = UInt(Zn); constant integer d = UInt(Zd); constant integer part = UInt(i2);
| 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 | i3h | 1 | Zm | 1 | 0 | 1 | i3l | 1 | 0 | Zn | Zd | |||||||||||||
if ((!IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME2)) || !IsFeatureImplemented(FEAT_LUT)) then UNDEFINED; constant integer isize = 2; constant integer esize = 16; constant integer m = UInt(Zm); constant integer n = UInt(Zn); constant integer d = UInt(Zd); constant integer part = UInt(i3h:i3l);
| <Zd> |
Is the name of the destination scalable vector register, encoded in the "Zd" field. |
| <Zn> |
Is the name of the table vector register, encoded in the "Zn" field. |
| <Zm> |
Is the name of the source scalable vector register, encoded in the "Zm" field. |
CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer elements = VL DIV esize; constant integer ibase = elements * part; constant bits(VL) indices = Z[m, VL]; constant bits(VL) table = Z[n, VL]; bits(VL) result; for e = 0 to elements-1 constant integer index = UInt(Elem[indices, ibase + e, isize]); Elem[result, e, esize] = Elem[table, index, esize]; Z[d, VL] = result;
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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