INS (element)

Insert vector element from another vector element

This instruction copies the vector element of the source SIMD&FP register to the specified vector element of the destination SIMD&FP register.

This instruction can insert data into individual elements within a SIMD&FP register without clearing the remaining bits to zero.

Depending on the settings in the CPACR_EL1, CPTR_EL2, and CPTR_EL3 registers, and the current Security state and Exception level, an attempt to execute the instruction might be trapped.

Encoding: Advanced SIMD

Variants: FEAT_AdvSIMD (ARMv8.0)

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	1	0	1	1	1	0	0	0	0						0					1
	Q	op									imm5						imm4					Rn					Rd

INS <Vd>.<Ts>[<index1>], <Vn>.<Ts>[<index2>]

Decoding algorithm

if !IsFeatureImplemented(FEAT_AdvSIMD) then EndOfDecode(Decode_UNDEF);
if imm5 IN 'x0000' then EndOfDecode(Decode_UNDEF);
constant integer size = LowestSetBitNZ(imm5<3:0>);

constant integer d = UInt(Rd);
constant integer n = UInt(Rn);
constant integer dst_index = UInt(imm5<4:size+1>);
constant integer src_index = UInt(imm4<3:size>);
constant integer idxdsize = 64 << UInt(imm4<3>);
// imm4 is IGNORED
constant integer esize = 8 << size;

Operation

CheckFPAdvSIMDEnabled64();
constant bits(idxdsize) operand = V[n, idxdsize];
bits(128) result;

result = V[d, 128];
Elem[result, dst_index, esize] = Elem[operand, src_index, esize];
V[d, 128] = result;

Explanations

<Vd>: Is the name of the SIMD&FP destination register, encoded in the "Rd" field.
<Ts>: <index1>: <Vn>: Is the name of the SIMD&FP source register, encoded in the "Rn" field.
<index2>:

Operational Notes

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.