VEXTRACTI128 — Extract packed Integer Values

Opcode/Instruction Op/En 64/32-bit Mode CPUID Feature Flag Description

VEX.256.66.0F3A.W0 39 /r ib

VEXTRACTI128 xmm1/m128, ymm2, imm8

 RMI V/V AVX2 Extract 128 bits of integer data from ymm2 and store results in xmm1/mem.

Instruction Operand Encoding

Op/En Operand 1 Operand 2 Operand 3 Operand 4
RMI ModRM:r/m (w) ModRM:reg (r) Imm8 NA

Description

Extracts 128-bits of packed integer values from the source operand (second operand) at a 128-bit offset from imm8[0] into the destination operand (first operand). The destination may be either an XMM register or a 128-bit memory location.

VEX.vvvv is reserved and must be 1111b otherwise instructions will #UD.

The high 7 bits of the immediate are ignored.

An attempt to execute VEXTRACTI128 encoded with VEX.L= 0 will cause an #UD exception.

Operation

VEXTRACTI128 (memory destination form)

CASE (imm8[0]) OF
    0: DEST[127:0] ← SRC1[127:0]
    1: DEST[127:0] ← SRC1[255:128]
ESAC.

VEXTRACTI128 (register destination form)

CASE (imm8[0]) OF
    0: DEST[127:0] ← SRC1[127:0]
    1: DEST[127:0] ← SRC1[255:128]
ESAC.
DEST[VLMAX-1:128] ← 0

Intel C/C++ Compiler Intrinsic Equivalent

VEXTRACTI128:

__m128i _mm256_extracti128_si256(__m256i a, int offset);

SIMD Floating-Point Exceptions

None

Other Exceptions

See Exceptions Type 6; additionally

#UD

IF VEX.L = 0,

If VEX.W = 1.