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LUTI6 (16-bit)

Lookup table read with 6-bit indices (16-bit)

This instruction copies indexed 16-bit elements from the low 512 bits of the two table vectors to the destination vector using packed 6-bit indices from a segment in the bottom three quarters of the source vector register.

This instruction is unpredicated.

This instruction requires that the Effective SVE vector length is at least 512 bits.

SVE2 class

(FEAT_SVE2p3 || FEAT_SME2p3)

313029282726252423222120191817161514131211109876543210
01000101i111Zm101011ZnZd

Encoding

LUTI6 <Zd>.H, { <Zn1>.H, <Zn2>.H }, <Zm>[<index>]

Decode

if !IsFeatureImplemented(FEAT_SVE2p3) && !IsFeatureImplemented(FEAT_SME2p3) then EndOfDecode(Decode_UNDEF); if MaxImplementedAnyVL() < 512 then EndOfDecode(Decode_UNDEF); constant integer isize = 6; constant integer esize = 16; constant integer m = UInt(Zm); constant integer n = UInt(Zn); constant integer d = UInt(Zd); constant integer part = UInt(i1);

Assembler Symbols

<Zd>

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

<Zn1>

Is the name of the first table vector register, encoded as "Zn".

<Zn2>

Is the name of the second table vector register, encoded as "Zn" plus 1 modulo 32.

<Zm>

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

<index>

Is the vector segment index, in the range 0 to 1, encoded in the "i1" field.

Operation

CheckSVEEnabled(); constant integer VL = CurrentVL; if VL < 512 then EndOfDecode(Decode_UNDEF); constant integer elements = VL DIV esize; constant integer ibase = elements * part; constant bits(VL) indexes = Z[m, VL]; // Only bottom 3/4 used constant bits(1024) table = Z[(n+1) MOD 32, VL]<511:0> : Z[n+0, VL]<511:0>; bits(VL) result; for e = 0 to elements-1 constant integer index = UInt(Elem[indexes, ibase + e, isize]); constant bits(esize) res = Elem[table, index, esize]; Elem[result, e, esize] = res; Z[d, VL] = result;

Operational information

This instruction is a data-independent-time instruction as described in About PSTATE.DIT.

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