UMOV Unsigned move vector element to general-purpose register This instruction reads the unsigned integer from the source SIMD&FP register, zero-extends it to form a 32-bit or 64-bit value, and writes the result to the destination general-purpose register. 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 a data-independent-time instruction as described in About PSTATE.DIT. This instruction is used by the alias MOV (to general) imm5 IN {'xx100'} imm5 IN {'x1000'} See below for details of when the alias is preferred. 0 0 0 1 1 1 0 0 0 0 0 0 1 1 1 1 0 UMOV <Wd>, <Vn>.<Ts>[<index>] 1 1 0 0 0 UMOV <Xd>, <Vn>.D[<index>] 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 esize : integer{} = 8 << size; let datasize : integer{} = 32 << UInt(Q); if datasize == 64 && esize < 64 then EndOfDecode(Decode_UNDEF); end; if datasize == 32 && esize >= 64 then EndOfDecode(Decode_UNDEF); end; let index : integer = UInt(imm5[4:size+1]); let idxdsize : integer{} = 64 << UInt(imm5[4]); <Wd> Is the 32-bit name of the general-purpose destination register, encoded in the "Rd" field. <Vn> Is the name of the SIMD&FP source register, encoded in the "Rn" field. <Ts> Is an element size specifier, imm5 <Ts> xx000 RESERVED xxxx1 B xxx10 H xx100 S <index> For the "32-bit" variant: is the element index imm5 <index> xx000 RESERVED xxxx1 UInt(imm5[4:1]) xxx10 UInt(imm5[4:2]) xx100 UInt(imm5[4:3]) <index> For the "64-bit" variant: is the element index encoded in "imm5<4>". <Xd> Is the 64-bit name of the general-purpose destination register, encoded in the "Rd" field. Alias Conditions if index == 0 then AArch64_CheckFPEnabled(); else AArch64_CheckFPAdvSIMDEnabled(); end; let operand : bits(idxdsize) = V{}(n); X{datasize}(d) = ZeroExtend{datasize}(operand[index*:esize]); 2026-03-12 12:23:09 2025-09_rel_asl1