Base Instructions | SIMD&FP Instructions | SVE Instructions | SME Instructions | Index by Encoding | Shared Pseudocode | Proprietary Notice

## AUTIA, AUTIA1716, AUTIASP, AUTIAZ, AUTIZA

Authenticate Instruction address, using key A. This instruction authenticates an instruction address, using a modifier and key A.

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 AUTIA and AUTIZA.
- In X17, for AUTIA1716.
- In X30, for AUTIASP and AUTIAZ.

The modifier is:

- In the general-purpose register or stack pointer that is specified by <Xn|SP> for AUTIA.
- The value zero, for AUTIZA and AUTIAZ.
- In X16, for AUTIA1716.
- In SP, for AUTIASP.

If FEAT_PAuth_LR is implemented and PSTATE.PACM is 1, then AUTIA1716 and AUTIASP include a second modifier that is:

- In X15, for AUTIA1716.
- In X16, for AUTIASP.

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 | 0 | Rn | Rd

#### AUTIA (Z == 0)

AUTIA <Xd>, <Xn|SP>

#### AUTIZA (Z == 1 && Rn == 11111)

AUTIZA <Xd>

boolean source_is_sp = FALSE; boolean autia1716 = FALSE; integer d = UInt(Rd); integer n = UInt(Rn); if !IsFeatureImplemented(FEAT_PAuth) then UNDEFINED; if Z == '0' then // AUTIA if n == 31 then source_is_sp = TRUE; else // AUTIZA 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 | 0 | x | 1 | 1 | 1 | 1 | 1
|  |  |  |  | CRm | op2 |

#### AUTIA1716 (CRm == 0001 && op2 == 100)

AUTIA1716

#### AUTIASP (CRm == 0011 && op2 == 101)

AUTIASP

#### AUTIAZ (CRm == 0011 && op2 == 100)

AUTIAZ

integer d; integer n; boolean source_is_sp = FALSE; boolean autia1716 = FALSE; case CRm:op2 of when '0011 100' // AUTIAZ d = 30; n = 31; when '0011 101' // AUTIASP d = 30; source_is_sp = TRUE; when '0001 100' // AUTIA1716 d = 17; n = 16; autia1716 = TRUE; when '0001 000' SEE "PACIA"; when '0001 010' SEE "PACIB"; when '0001 110' SEE "AUTIB"; when '0011 00x' SEE "PACIA"; when '0011 01x' SEE "PACIB"; when '0011 11x' SEE "AUTIB"; 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] = AuthIA2(X[d, 64], SP[], X[16, 64], FALSE); else X[d, 64] = AuthIA(X[d, 64], SP[], FALSE); else if IsFeatureImplemented(FEAT_PAuth_LR) && PSTATE.PACM == '1' && autia1716 then X[d, 64] = AuthIA2(X[d, 64], X[n, 64], X[15, 64], FALSE); else X[d, 64] = AuthIA(X[d, 64], X[n, 64], FALSE);

Base Instructions | SIMD&FP Instructions | SVE Instructions | SME Instructions | Index by Encoding | Shared Pseudocode | Proprietary Notice

Internal version only: isa v33.74, AdvSIMD v29.23, pseudocode v2023-09_rel, sve v2023-09_rc3 ; Build timestamp: 2023-09-27T17:06

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