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.

This instruction is used by the alias MOV (element).

Advanced SIMD
(FEAT_AdvSIMD)

313029282726252423222120191817161514131211109876543210
01101110000imm50imm41RnRd
Qop

Encoding

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

Decode for this encoding

if !IsFeatureImplemented(FEAT_AdvSIMD) then EndOfDecode(Decode_UNDEF); end; if imm5 == 'x0000' then EndOfDecode(Decode_UNDEF); end; let size : integer{} = LowestSetBitNZ(imm5[3:0]); let d : integer{} = UInt(Rd); let n : integer{} = UInt(Rn); let dst_index : integer = UInt(imm5[4:size+1]); let src_index : integer = UInt(imm4[3:size]); let idxdsize : integer{} = 64 << UInt(imm4[3]); // imm4<size-1:0> is IGNORED let esize : integer{} = 8 << size;

Assembler Symbols

<Vd>

Is the name of the SIMD&FP destination register, encoded in the "Rd" field.

<Ts>

Is an element size specifier, encoded in imm5:

imm5 <Ts>
x0000 RESERVED
xxxx1 B
xxx10 H
xx100 S
x1000 D
<index1>

Is the destination element index encoded in imm5:

imm5 <index1>
x0000 RESERVED
xxxx1 UInt(imm5[4:1])
xxx10 UInt(imm5[4:2])
xx100 UInt(imm5[4:3])
x1000 UInt(imm5[4])
<Vn>

Is the name of the SIMD&FP source register, encoded in the "Rn" field.

<index2>

Is the source element index encoded in (imm5 :: imm4):

imm5 <index2>
x0000 RESERVED
xxxx1 UInt(imm4)
xxx10 UInt(imm4[3:1])
xx100 UInt(imm4[3:2])
x1000 UInt(imm4[3])
Unspecified bits in "imm4" are ignored but should be set to zero by an assembler.

Operation

AArch64_CheckFPAdvSIMDEnabled(); let operand : bits(idxdsize) = V{}(n); var result : bits(128); result = V{128}(d); result[dst_index*:esize] = operand[src_index*:esize]; V{128}(d) = result;

Operational information

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


2026-03_rel 2026-03-26 20:48:11

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