ADDPT Add checked pointer This instruction adds a base address register value and an optionally-shifted register value, and writes the result to the destination register. The optionally-shifted register value is treated as the offset. If the operation would have generated a result where the most significant 8 bits of the result register differ from the most significant 8 bits of the base register, then the result is modified such that it is likely to be non-canonical when used as an address. 1 0 0 1 1 0 1 0 0 0 0 0 0 1 ADDPT <Xd|SP>, <Xn|SP>, <Xm>{, LSL #<amount>} if !IsFeatureImplemented(FEAT_CPA) then EndOfDecode(Decode_UNDEF); end; let d : integer{} = UInt(Rd); let n : integer{} = UInt(Rn); let m : integer{} = UInt(Rm); let shift : integer = UInt(imm3); <Xd|SP> Is the 64-bit name of the general-purpose destination register or stack pointer, encoded in the "Rd" field. <Xn|SP> Is the 64-bit name of the first general-purpose source 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. <amount> Is the left shift amount, in the range 0 to 7, defaulting to 0, encoded in the "imm3" field. var result : bits(64); let base : bits(64) = if n == 31 then SP{64}() else X{64}(n); let offset : bits(64) = LSL(X{64}(m), shift); result = base + offset; result = PointerAddCheck(result, base); if d == 31 then SP{64}() = result; else X{64}(d) = result; end; 2026-03-12 12:23:09 2025-09_rel_asl1