Arm® A64 Instruction Set Architecture: Armv8, for Armv8-A architecture profile

AUTIB, AUTIB1716, AUTIBSP, AUTIBZ, AUTIZB

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

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 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.

It has encodings from 2 classes: Integer and System

Integer
(Armv8.3)

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

if !HavePACExt() then
    UNDEFINED;

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

System
(Armv8.3)

integer d;
integer n;
boolean source_is_sp = 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;
    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

auth_then_branch = FALSE;

if HavePACExt() then
    if source_is_sp then
        X[d] = AuthIB(X[d], SP[], auth_then_branch);
    else
        X[d] = AuthIB(X[d], X[n], auth_then_branch);