autda

Authenticate Data Address (Key A)

AUTDA <Xd>, <Xn>

Authenticates a data address signed with Key A.

Pseudocode Operation

Xd ← AuthDA(Xd, Xn)

Example

AUTDA x0, x1

Encoding

Binary Layout

1

31

1

30

0

29

11010110

28:21

00001

20:16

00

15:14

0

13

110

12:10

Rn

9:5

Rd

4:0

 

Format Data Processing

Opcode 0xDAC11800

Extension PAC (Security)

Operands

• Xd
  Destination 64-bit integer register
• Xn
  Modifier

Related

More in PAC (Security)

Reference

View in Arm A64 ISA Reference ↗ Arm A64 ISA

Instruction Forms

Encoding	Instruction		ISA		Bit pattern
0xDAC11800	AUTDA <Xd>, <Xn|SP>		A64		1 | 1 | 0 | 11010110 | 00001 | 00 | 0 | 110 | Rn | Rd

Description

Authenticate Data address, using key A. This instruction authenticates a data address, using a modifier and key A. The address is in the general-purpose register that is specified by <Xd>. The modifier is: 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.

Operation

if IsFeatureImplemented(FEAT_PAuth) then
    if source_is_sp then
        X[d, 64] = AuthDA(X[d, 64], SP[], FALSE);
    else
        X[d, 64] = AuthDA(X[d, 64], X[n, 64], FALSE);