LUTI2 Lookup table read with 2-bit indices This instruction copies indexed 8-bit or 16-bit elements from 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. 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. 0 1 0 0 1 1 1 0 1 x 0 0 0 0 0 1 LUTI2 <Vd>.16B, { <Vn>.16B }, <Vm>[<index>] 1 LUTI2 <Vd>.8H, { <Vn>.8H }, <Vm>[<index>] if !IsFeatureImplemented(FEAT_LUT) then UNDEFINED; if op2 == '10' && op == '0' then UNDEFINED; constant integer d = UInt(Rd); constant integer n = UInt(Rn); constant integer m = UInt(Rm); constant integer isize = 2; constant integer esize = if op2 == '10' then 8 else 16; constant integer part = if op2 == '10' then UInt(len) else UInt(len:op); <Vd> Is the name of the SIMD&FP destination register, encoded in the "Rd" field. <Vn> Is the name of the SIMD&FP table register, encoded in the "Rn" field. <Vm> Is the name of the SIMD&FP source register, encoded in the "Rm" field. <index> For the byte variant: is the vector segment index, in the range 0 to 3, encoded in the "len" field. <index> For the halfword variant: is the vector segment index, in the range 0 to 7, encoded in the "len:op" fields. CheckFPAdvSIMDEnabled64(); constant integer elements = 128 DIV esize; constant integer ibase = elements * part; constant bits(128) indices = V[m, 128]; constant bits(128) table = V[n, 128]; bits(128) result; for e = 0 to elements-1 constant integer index = UInt(Elem[indices, ibase + e, isize]); Elem[result, e, esize] = Elem[table, index, esize]; V[d, 128] = result;