PACIA, PACIA1716, PACIASP, PACIAZ, PACIZA

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

The address is:

The modifier is:

If FEAT_PAuth_LR is implemented and PSTATE.PACM is 1, then PACIA1716 and PACIASP include a second modifier that is:

A PACIASP instruction has an implicit BTI instruction. The implicit BTI instruction of a PACIASP instruction is always compatible with PSTATE.BTYPE == 0b01 and PSTATE.BTYPE == 0b10. Controls in SCTLR_ELx configure whether the implicit BTI instruction of a PACIASP instruction is compatible with PSTATE.BTYPE == 0b11. For more information, see PSTATE.BTYPE.

It has encodings from 2 classes: Integer and System

Integer
(FEAT_PAuth)

313029282726252423222120191817161514131211109876543210
110110101100000100Z000RnRd
sfSopcode2

PACIA (Z == 0)

PACIA <Xd>, <Xn|SP>

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

PACIZA <Xd>

if !IsFeatureImplemented(FEAT_PAuth) then UNDEFINED; boolean source_is_sp = FALSE; boolean pacia1716 = FALSE; integer d = UInt(Rd); integer n = UInt(Rn); if Z == '0' then // PACIA if n == 31 then source_is_sp = TRUE; else // PACIZA if n != 31 then UNDEFINED;

System
(FEAT_PAuth)

313029282726252423222120191817161514131211109876543210
1101010100000011001000x100x11111
CRmop2

PACIA1716 (CRm == 0001 && op2 == 000)

PACIA1716

PACIASP (CRm == 0011 && op2 == 001)

PACIASP

PACIAZ (CRm == 0011 && op2 == 000)

PACIAZ

if !IsFeatureImplemented(FEAT_PAuth) then EndOfInstruction(); // Instruction executes as NOP integer d; integer n; boolean source_is_sp = FALSE; boolean pacia1716 = FALSE; case CRm:op2 of when '0011 000' // PACIAZ d = 30; n = 31; when '0011 001' // PACIASP d = 30; source_is_sp = TRUE; if IsFeatureImplemented(FEAT_BTI) then // Check for branch target compatibility between PSTATE.BTYPE // and implicit branch target of PACIASP instruction. SetBTypeCompatible(BTypeCompatible_PACIXSP()); when '0001 000' // PACIA1716 d = 17; n = 16; pacia1716 = TRUE; when '0001 010' SEE "PACIB"; when '0001 100' SEE "AUTIA"; when '0001 110' SEE "AUTIB"; when '0011 01x' SEE "PACIB"; when '0011 10x' SEE "AUTIA"; 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 source_is_sp then if IsFeatureImplemented(FEAT_PAuth_LR) && PSTATE.PACM == '1' then X[d, 64] = AddPACIA2(X[d, 64], SP[], PC64); else X[d, 64] = AddPACIA(X[d, 64], SP[]); else if IsFeatureImplemented(FEAT_PAuth_LR) && PSTATE.PACM == '1' && pacia1716 then X[d, 64] = AddPACIA2(X[d, 64], X[n, 64], X[15, 64]); else X[d, 64] = AddPACIA(X[d, 64], X[n, 64]);


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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