LDRAA, LDRAB

Load register, with pointer authentication

This instruction authenticates an address from a base register using a modifier of zero and the specified key, adds an immediate offset to the authenticated address, and loads a 64-bit doubleword from memory at this resulting address into a register.

Key A is used for LDRAA. Key B is used for LDRAB.

If the authentication passes, the PE behaves the same as for an LDR instruction. For information on behavior if the authentication fails, see Faulting on pointer authentication.

The authenticated address is not written back to the base register, unless the pre-indexed variant of the instruction is used. In this case, the address that is written back to the base register does not include the pointer authentication code.

For information about addressing modes, see Load/Store addressing modes.

PAC
(FEAT_PAuth)

Decode for all variants of this encoding

if !IsFeatureImplemented(FEAT_PAuth) then EndOfDecode(Decode_UNDEF); constant integer t = UInt(Rt); constant integer n = UInt(Rn); boolean wback = W == '1'; constant boolean use_key_a = M == '0'; constant bits(10) S10 = S:imm9; constant bits(64) offset = LSL(SignExtend(S10, 64), 3); constant boolean nontemporal = FALSE; constant boolean tagchecked = wback || n != 31; boolean wb_unknown = FALSE; if wback && n == t && n != 31 then constant Constraint c = ConstrainUnpredictable(Unpredictable_WBOVERLAPLD); assert c IN {Constraint_WBSUPPRESS, Constraint_UNKNOWN, Constraint_UNDEF, Constraint_NOP}; case c of when Constraint_WBSUPPRESS wback = FALSE; // writeback is suppressed when Constraint_UNKNOWN wb_unknown = TRUE; // writeback is UNKNOWN when Constraint_UNDEF EndOfDecode(Decode_UNDEF); when Constraint_NOP EndOfDecode(Decode_NOP);