MOVSHDUP (Move Packed Single-FP High and Duplicate)

Opcodes

Opcode/Instruction Op/En 64/32-bit Mode CPUID Feature Flag Description
F3 0F 16 /r MOVSHDUP xmm1, xmm2/m128 RM V/V SSE3 Move two single-precision floating-point values from the higher 32-bit operand of each qword in xmm2/m128 to xmm1 and duplicate each 32-bit operand to the lower 32-bits of each qword.
VEX.128.F3.0F.WIG 16 /r VMOVSHDUP xmm1, xmm2/m128 RM V/V AVX Move odd index single-precision floating-point values from xmm2/mem and duplicate each element into xmm1.
VEX.256.F3.0F.WIG 16 /r VMOVSHDUP ymm1, ymm2/m256 RM V/V AVX Move odd index single-precision floating-point values from ymm2/mem and duplicate each element into ymm1.

Instruction Operand Encoding

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

Description

The linear address corresponds to the address of the least-significant byte of the referenced memory data. When a memory address is indicated, the 16 bytes of data at memory location m128 are loaded and the single-precision elements in positions 1 and 3 are duplicated. When the register-register form of this operation is used, the same operation is performed but with data coming from the 128-bit source register. See Figure 3-25.

Figure 3-25. MOVSHDUP—Move Packed Single-FP High and Duplicate

In 64-bit mode, use of the REX prefix in the form of REX.R permits this instruction to access additional registers (XMM8-XMM15).

128-bit Legacy SSE version: Bits (VLMAX-1:128) of the corresponding YMM destination register remain unchanged.

VEX.128 encoded version: Bits (VLMAX-1:128) of the destination YMM register are zeroed.

Note: In VEX-encoded versions, VEX.vvvv is reserved and must be 1111b otherwise instructions will #UD.

Operation

MOVSHDUP (128-bit Legacy SSE version)

DEST[31:0] ← SRC[63:32]
DEST[63:32] ← SRC[63:32]
DEST[95:64] ← SRC[127:96]
DEST[127:96] ← SRC[127:96]
DEST[VLMAX-1:128] (Unmodified)

VMOVSHDUP (VEX.128 encoded version)

DEST[31:0] ← SRC[63:32]
DEST[63:32] ← SRC[63:32]
DEST[95:64] ← SRC[127:96]
DEST[127:96] ← SRC[127:96]
DEST[VLMAX-1:128] ← 0

VMOVSHDUP (VEX.256 encoded version)

DEST[31:0] ← SRC[63:32]
DEST[63:32] ← SRC[63:32]
DEST[95:64] ← SRC[127:96]
DEST[127:96] ← SRC[127:96]
DEST[159:128] ← SRC[191:160]
DEST[191:160] ← SRC[191:160]
DEST[223:192] ← SRC[255:224]
DEST[255:224] ← SRC[255:224]

Intel C/C++ Compiler Intrinsic Equivalent

(V)MOVSHDUP:

__m128 _mm_movehdup_ps(__m128 a)

VMOVSHDUP:

__m256 _mm256_movehdup_ps (__m256 a);

Exceptions

General protection exception if not aligned on 16-byte boundary, regardless of segment.

Numeric Exceptions

None

Other Exceptions

See Exceptions Type 2.