AESENCLAST (Perform Last Round of an AES Encryption Flow)

Opcodes

Opcode/Instruction Op/En 64/32-bit Mode CPUID Feature Flag Description
66 0F 38 DD /r AESENCLAST xmm1, xmm2/m128 RM V/V AES Perform the last round of an AES encryption flow, operating on a 128-bit data (state) from xmm1 with a 128-bit round key from xmm2/m128.
VEX.NDS.128.66.0F38.WIG DD /r VAESENCLAST xmm1, xmm2, xmm3/m128 RVM V/V Both AES and AVX flags Perform the last round of an AES encryption flow, operating on a 128-bit data (state) from xmm2 with a 128 bit round key from xmm3/m128; store the result in xmm1.

Instruction Operand Encoding

Op/En Operand 1 Operand2 Operand3 Operand4
RM ModRM:reg (r, w) ModRM:r/m (r) NA NA
RVM ModRM:reg (w) VEX.vvvv (r) ModRM:r/m (r) NA

Description

This instruction performs the last round of an AES encryption flow using a round key from the second source operand, operating on 128-bit data (state) from the first source operand, and store the result in the destination operand.

128-bit Legacy SSE version: The first source operand and the destination operand are the same and must be an XMM register. The second source operand can be an XMM register or a 128-bit memory location. Bits (VLMAX-1:128) of the corresponding YMM destination register remain unchanged.

VEX.128 encoded version: The first source operand and the destination operand are XMM registers. The second source operand can be an XMM register or a 128-bit memory location. Bits (VLMAX-1:128) of the destination YMM register are zeroed.

Operation

AESENCLAST

STATE ← SRC1;
RoundKey ← SRC2;
STATE ← ShiftRows( STATE );
STATE ← SubBytes( STATE );
DEST[127:0] ← STATE XOR RoundKey;
DEST[VLMAX-1:128] (Unmodified)

VAESENCLAST

STATE ← SRC1;
RoundKey ← SRC2;
STATE ← ShiftRows( STATE );
STATE ← SubBytes( STATE );
DEST[127:0] ← STATE XOR RoundKey;
DEST[VLMAX-1:128] ← 0

Intel C/C++ Compiler Intrinsic Equivalent

(V)AESENCLAST:

__m128i _mm_aesenclast (__m128i, __m128i)

SIMD Floating-Point Exceptions

None

Other Exceptions

See Exceptions Type 4.