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SIMD ISAReturn TypeNameArgumentsInstruction Group
Neonpoly8x16_tvqtbl3q_p8(poly8x16x3_t t, uint8x16_t idx)Table lookup / Table lookup
Description
Table vector Lookup. This instruction reads each value from the vector elements in the index source SIMD&FP register, uses each result as an index to perform a lookup in a table of bytes that is described by one to four source table SIMD&FP registers, places the lookup result in a vector, and writes the vector to the destination SIMD&FP register. If an index is out of range for the table, the result for that lookup is 0. If more than one source register is used to describe the table, the first source register describes the lowest bytes of the table.
Results
Vd.16B result
This intrinsic compiles to the following instructions:

TBL Vd.16B,{Vn.16B - Vn+2.16B},Vm.16B

Argument Preparation
t register: Vn.16Bidx register: Vm.16B
Architectures
A64

Operation

CheckFPAdvSIMDEnabled64();
bits(datasize) indices = V[m];
bits(128*regs) table = Zeros();
bits(datasize) result;
integer index;

// Create table from registers
for i = 0 to regs - 1
    table<128*i+127:128*i> = V[n];
    n = (n + 1) MOD 32;

result = if is_tbl then Zeros() else V[d];
for i = 0 to elements - 1
    index = UInt(Elem[indices, i, 8]);
    if index < 16 * regs then
        Elem[result, i, 8] = Elem[table, index, 8];

V[d] = result;