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

## 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

### 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
sf |  | S |  | opcode2 |  |  |  |  |

#### AUTIB (Z == 0)

AUTIB <Xd>, <Xn|SP>

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

AUTIZB <Xd>

if !IsFeatureImplemented(FEAT_PAuth) then UNDEFINED; if Z == '1' && Rn != '11111' then UNDEFINED; boolean autib1716 = FALSE; integer d = UInt(Rd); integer n = UInt(Rn); boolean auth_combined = FALSE; boolean source_is_sp = Z == '0' && n == 31;

### 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

if !IsFeatureImplemented(FEAT_PAuth) then EndOfInstruction(); // Instruction executes as NOP integer d; integer n; boolean source_is_sp = FALSE; boolean autib1716 = FALSE; boolean auth_combined = 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 source_is_sp then if IsFeatureImplemented(FEAT_PAuth_LR) && PSTATE.PACM == '1' then X[d, 64] = AuthIB2(X[d, 64], SP[], X[16, 64], auth_combined); else X[d, 64] = AuthIB(X[d, 64], SP[], auth_combined); else if IsFeatureImplemented(FEAT_PAuth_LR) && PSTATE.PACM == '1' && autib1716 then X[d, 64] = AuthIB2(X[d, 64], X[n, 64], X[15, 64], auth_combined); else X[d, 64] = AuthIB(X[d, 64], X[n, 64], auth_combined);

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

Internal version only: aarchmrs v2024-03_relA, pseudocode v2024-03_rel, sve v2024-03_rel ; Build timestamp: 2024-03-26T09:45

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