AUTIB, AUTIB1716, AUTIBSP, AUTIBZ, AUTIZB
Authenticate instruction address, using key B
This instruction authenticates an instruction address, using a modifier and key B.
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.
The address is:
In the general-purpose register that is specified by
<Xd> for AUTIB and AUTIZB.
In X17, for AUTIB1716.
In X30, for AUTIBSP and AUTIBZ.
The modifier is:
In the general-purpose register or stack pointer that is specified
by <Xn|SP> for AUTIB.
The value zero, for AUTIZB and AUTIBZ.
In X16, for AUTIB1716.
In SP, for AUTIBSP.
If FEAT_PAuth_LR is implemented and PSTATE.PACM is 1, then
AUTIB1716 and AUTIBSP include a second modifier that is:
In X15, for AUTIB1716.
In X16, for AUTIBSP.
It has encodings from 2 classes:
Integer
and
System
1
1
0
1
1
0
1
0
1
1
0
0
0
0
0
1
0
0
1
0
1
0
AUTIB <Xd>, <Xn|SP>
1
1
1
1
1
1
AUTIZB <Xd>
if !IsFeatureImplemented(FEAT_PAuth) then EndOfDecode(Decode_UNDEF); end;
if Z == '1' && Rn != '11111' then EndOfDecode(Decode_UNDEF); end;
let autib1716 : boolean = FALSE;
let d : integer = UInt(Rd);
let n : integer = UInt(Rn);
let auth_combined : boolean = FALSE;
let source_is_sp : boolean = Z == '0' && n == 31;
1
1
0
1
0
1
0
1
0
0
0
0
0
0
1
1
0
0
1
0
0
0
x
1
1
1
x
1
1
1
1
1
0
0
AUTIB1716
1
1
AUTIBSP
1
0
AUTIBZ
if !IsFeatureImplemented(FEAT_PAuth) then EndOfDecode(Decode_NOP); end;
var d : integer;
var n : integer;
var source_is_sp : boolean = FALSE;
var autib1716 : boolean = FALSE;
let auth_combined : boolean = FALSE;
case CRm::op2 of
when '0011 110' => // AUTIBZ
d = 30;
n = 31;
when '0011 111' => // AUTIBSP
d = 30;
source_is_sp = TRUE;
when '0001 110' => // AUTIB1716
d = 17;
n = 16;
autib1716 = TRUE;
end;
<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
if IsFeatureImplemented(FEAT_PAuth_LR) && PSTATE.PACM == '1' then
X{64}(d) = AuthIB2(X{64}(d), SP{64}(), X{64}(16), auth_combined);
else
X{64}(d) = AuthIB(X{64}(d), SP{64}(), auth_combined);
end;
else
if IsFeatureImplemented(FEAT_PAuth_LR) && PSTATE.PACM == '1' && autib1716 then
X{64}(d) = AuthIB2(X{64}(d), X{64}(n), X{64}(15), auth_combined);
else
X{64}(d) = AuthIB(X{64}(d), X{64}(n), auth_combined);
end;
end;
2026-03-26 20:27:25
2026-03_rel