You copied the Doc URL to your clipboard.


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. If the authentication fails, the upper bits are corrupted and any subsequent use of the address results in a Translation fault.



AUTDB (Z == 0)

AUTDB <Xd>, <Xn|SP>

AUTDZB (Z == 1 && Rn == 11111)


boolean source_is_sp = FALSE;
integer d = UInt(Rd);
integer n = UInt(Rn);

if !HavePACExt() then

if Z == '0' then // AUTDB
    if n == 31 then source_is_sp = TRUE;
else // AUTDZB
    if n != 31 then UNDEFINED;

Assembler Symbols


Is the 64-bit name of the general-purpose destination register, encoded in the "Rd" field.


Is the 64-bit name of the general-purpose source register or stack pointer, encoded in the "Rn" field.


if HavePACExt() then
    if source_is_sp then
        X[d] = AuthDB(X[d], SP[], FALSE);
        X[d] = AuthDB(X[d], X[n], FALSE);