AUTDB, AUTDZB Authenticate data address, using key B This instruction authenticates a data address, using a modifier and key B. The address is in the general-purpose register that is specified by <Xd>. The modifier is: In the general-purpose register or stack pointer that is specified by <Xn|SP> for AUTDB. The value zero, for AUTDZB. If the authentication passes, the upper bits of the address are restored to enable subsequent use of the address. For information on behavior if the authentication fails, see Faulting on pointer authentication. 1 1 0 1 1 0 1 0 1 1 0 0 0 0 0 1 0 0 1 1 1 0 AUTDB <Xd>, <Xn|SP> 1 1 1 1 1 1 AUTDZB <Xd> if !IsFeatureImplemented(FEAT_PAuth) then EndOfDecode(Decode_UNDEF); end; if Z == '1' && Rn != '11111' then EndOfDecode(Decode_UNDEF); end; let auth_combined : boolean = FALSE; let d : integer = UInt(Rd); let n : integer = UInt(Rn); let source_is_sp : boolean = Z == '0' && n == 31; <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 general-purpose source register or stack pointer, encoded in the "Rn" field. if source_is_sp then X{64}(d) = AuthDB(X{64}(d), SP{64}(), auth_combined); else X{64}(d) = AuthDB(X{64}(d), X{64}(n), auth_combined); end; 2026-03-26 20:27:25 2026-03_rel