Arm® A64 Instruction Set Architecture: Future Architecture Technologies in the A architecture profile

AUTIA, AUTIA1716, AUTIASP, AUTIAZ, AUTIZA

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

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 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 // AUTIA
    if n == 31 then source_is_sp = TRUE;
else // AUTIZA
    if n != 31 then UNDEFINED;

System
(Armv8.3)

integer d;
integer n;
boolean source_is_sp = 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;
    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

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