GMI Tag mask insert This instruction inserts the tag in the first source register into the excluded set specified in the second source register, writing the new excluded set to the destination register. 1 0 0 1 1 0 1 0 1 1 0 0 0 0 1 0 1 GMI <Xd>, <Xn|SP>, <Xm> if !IsFeatureImplemented(FEAT_MTE) then EndOfDecode(Decode_UNDEF); end; let d : integer{} = UInt(Rd); let n : integer{} = UInt(Rn); let m : integer{} = UInt(Rm); <Xd> Is the 64-bit name of the general-purpose destination register, encoded in the "Rd" field. <Xn|SP> Is the 64-bit name of the first source general-purpose register or stack pointer, encoded in the "Rn" field. <Xm> Is the 64-bit name of the second general-purpose source register, encoded in the "Rm" field. let address : bits(64) = if n == 31 then SP{64}() else X{64}(n); var mask : bits(64) = X{}(m); let tag : bits(4) = AArch64_AllocationTagFromAddress(address); mask[UInt(tag)] = '1'; X{64}(d) = mask; 2026-03-12 12:23:09 2025-09_rel_asl1