MOVDDUP—Move One Double-FP and Duplicate

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 floatingpoint 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.

MOVDDUP xmm1, xmm2/m64

[63:0]

xmm2/m64

RESULT:

xmm1[127:64]

xmm2/m64[63:0][127:64]

xmm1[63:0]

xmm2/m64[63:0]xmm1 [63:0]

OM15997

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.