MOVDDUP (Move One Double-FP and Duplicate)

Opcodes

Opcode/Instruction Op/En 64/32-bit Mode CPUID Feature Flag Description
F2 0F 12 /r MOVDDUP xmm1, xmm2/m64 RM V/V SSE3 Move one double-precision floating-point value from the lower 64-bit operand in xmm2/m64 to xmm1 and duplicate.
VEX.128.F2.0F.WIG 12 /r VMOVDDUP xmm1, xmm2/m64 RM V/V AVX Move double-precision floating-point values from xmm2/mem and duplicate into xmm1.
VEX.256.F2.0F.WIG 12 /r VMOVDDUP ymm1, ymm2/m256 RM V/V AVX Move even index double-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 8 bytes of data at memory location m64 are loaded. When the register-register form of this operation is used, the lower half of the 128-bit source register is duplicated and copied into the 128-bit destination register. See Figure 3-24.

Figure 3-24. MOVDDUP—Move One Double-FP and Duplicate

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

Operation

IF (Source = m64)
    THEN
         (* Load instruction *)
         xmm1[63:0] = m64;
         xmm1[127:64] = m64;
    ELSE
         (* Move instruction *)
         xmm1[63:0] = xmm2[63:0];
         xmm1[127:64] = xmm2[63:0];
FI;

MOVDDUP (128-bit Legacy SSE version)

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

VMOVDDUP (VEX.128 encoded version)

DEST[63:0] ← SRC[63:0]
DEST[127:64] ← SRC[63:0]
DEST[VLMAX-1:128] ← 0

VMOVDDUP (VEX.256 encoded version)

DEST[63:0] ← SRC[63:0]
DEST[127:64] ← SRC[63:0]
DEST[191:128] ← SRC[191:128]
DEST[255:192] ← SRC[191:128]

Intel C/C++ Compiler Intrinsic Equivalent

MOVDDUP:

__m128d _mm_movedup_pd(__m128d a)

MOVDDUP:

__m128d _mm_loaddup_pd(double const * dp)

SIMD Floating-Point Exceptions

None

Other Exceptions

See Exceptions Type 5; additionally

#UD If VEX.vvvv ≠ 1111B.