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PACIB, PACIB1716, PACIBSP, PACIBZ, PACIZB

Pointer Authentication Code for Instruction address, using key B. This instruction computes and inserts a pointer authentication code for an instruction address, using a modifier and key B.

The address is:

  • In the general-purpose register that is specified by <Xd> for PACIB and PACIZB.
  • In X17, for PACIB1716.
  • In X30, for PACIBSP and PACIBZ.

The modifier is:

  • In the general-purpose register or stack pointer that is specified by <Xn|SP> for PACIB.
  • The value zero, for PACIZB and PACIBZ.
  • In X16, for PACIB1716.
  • In SP, for PACIBSP.

It has encodings from 2 classes: Integer and System

Integer
(Armv8.3)

313029282726252423222120191817161514131211109876543210
110110101100000100Z001RnRd

PACIB (Z == 0)

PACIB <Xd>, <Xn|SP>

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

PACIZB <Xd>

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

if !HavePACExt() then
    UNDEFINED;

if Z == '0' then // PACIB
    if n == 31 then source_is_sp = TRUE;
else // PACIZB
    if n != 31 then UNDEFINED;

System
(Armv8.3)

313029282726252423222120191817161514131211109876543210
1101010100000011001000x101x11111
CRmop2

PACIB1716 (CRm == 0001 && op2 == 010)

PACIB1716

PACIBSP (CRm == 0011 && op2 == 011)

PACIBSP

PACIBZ (CRm == 0011 && op2 == 010)

PACIBZ

integer d;
integer n;
boolean source_is_sp = FALSE;

case CRm:op2 of
    when '0011 010'    // PACIBZ
        d = 30;
        n = 31;
    when '0011 011'    // PACIBSP
        d = 30;
        source_is_sp = TRUE;
        if HaveBTIExt() then
            // Check for branch target compatibility between PSTATE.BTYPE
            // and implicit branch target of PACIBSP instruction.
            - = BTypeCompatible_PACIXSP();
    when '0001 010'    // PACIB1716
        d = 17;
        n = 16;
    when '0001 000' SEE "PACIA";
    when '0001 100' SEE "AUTIA";
    when '0001 110' SEE "AUTIB";
    when '0011 00x' SEE "PACIA";
    when '0011 10x' SEE "AUTIA";
    when '0011 11x' SEE "AUTIB";
    when '0000 111' SEE "XPACLRI";

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