aesd

AES Decrypt (A32)

AESD.8 <Qd>, <Qm>

Performs one round of AES decryption (AArch32).

Pseudocode Operation

state ← Qd
round_key ← Qm
state ← InvShiftRows(state)
state ← InvSubBytes(state)
state ← AddRoundKey(state, round_key)
state ← InvMixColumns(state)
Qd ← state

Example

AESD.8 q0, q2

Encoding

Binary Layout

11110011

31:24

1

23

D

22

11

21:20

00

19:18

00

17:16

Vd

15:12

00111

11:7

Q

6

M

5

0

4

Vm

3:0

 

Format Crypto 2-Reg

Opcode 0xF3B00340

Extension Crypto

Operands

• Qd
  Data
• Qm
  Key

Related

Other forms of aesd

• aesd AES Decrypt (A64)
• aesd AES Decrypt

More in Crypto

Reference

View in Arm A64 ISA Reference ↗ Arm A64 ISA

Instruction Forms

Encoding	Instruction		ISA		Bit pattern
0x4E285800	AESD <Vd>.16B, <Vn>.16B		A64		01001110 | 00 | 101000010 | 1 | 10 | Rn | Rd
0x4522E400	AESD <Zdn>.B, <Zdn>.B, <Zm>.B		A64		01000101 | 0 | 0 | 10001 | 0 | 11100 | 1 | Zm | Zdn

Description

AES single round decryption.

Operation

AArch64.CheckFPAdvSIMDEnabled();

bits(128) operand1 = V[d, 128];
bits(128) operand2 = V[n, 128];
bits(128) result;
result = operand1 EOR operand2;
result = AESInvSubBytes(AESInvShiftRows(result));
V[d, 128] = result;