Index

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:

The modifier is:

If FEAT_PAuth_LR is implemented and PSTATE.PACM is 1, then AUTIB1716 and AUTIBSP include a second modifier that is:

It has encodings from 2 classes: Integer and System

Integer
(FEAT_PAuth)

31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
1 1 0 1 1 0 1 0 1 1 0 0 0 0 0 1 0 0 Z 1 0 1 Rn Rd

AUTIB (Z == 0)

AUTIB <Xd>, <Xn|SP>

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

AUTIZB <Xd>

boolean source_is_sp = FALSE;
boolean autib1716 = FALSE;
integer d = UInt(Rd);
integer n = UInt(Rn);

if !IsFeatureImplemented(FEAT_PAuth) then
    UNDEFINED;

if Z == '0' then // AUTIB
    if n == 31 then source_is_sp = TRUE;
else // AUTIZB
    if n != 31 then UNDEFINED;

System
(FEAT_PAuth)

31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
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
CRm op2

AUTIB1716 (CRm == 0001 && op2 == 110)

AUTIB1716

AUTIBSP (CRm == 0011 && op2 == 111)

AUTIBSP

AUTIBZ (CRm == 0011 && op2 == 110)

AUTIBZ

integer d;
integer n;
boolean source_is_sp = FALSE;
boolean autib1716 = 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;
    when '0001 000' SEE "PACIA";
    when '0001 010' SEE "PACIB";
    when '0001 100' SEE "AUTIA";
    when '0011 00x' SEE "PACIA";
    when '0011 01x' SEE "PACIB";
    when '0011 10x' SEE "AUTIA";
    when '0000 111' SEE "XPACLRI";
    otherwise SEE "HINT";

Assembler Symbols

<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.

Operation

if IsFeatureImplemented(FEAT_PAuth) then
    if source_is_sp then
        if IsFeatureImplemented(FEAT_PAuth_LR) && PSTATE.PACM == '1' then
            X[d, 64] = AuthIB2(X[d, 64], SP[], X[16, 64], FALSE);
        else
            X[d, 64] = AuthIB(X[d, 64], SP[], FALSE);
    else
        if IsFeatureImplemented(FEAT_PAuth_LR) && PSTATE.PACM == '1' && autib1716 then
            X[d, 64] = AuthIB2(X[d, 64], X[n, 64], X[15, 64], FALSE);
        else
            X[d, 64] = AuthIB(X[d, 64], X[n, 64], FALSE);