MOVAPD—Move Aligned Packed Double-Precision Floating-Point Values

Instruction Operand Encoding

Description

Moves 2 or 4 double-precision floating-point values from the source operand (second operand) to the destination operand (first operand). This instruction can be used to load an XMM or YMM register from an 128-bit or 256-bit memory location, to store the contents of an XMM or YMM register into a 128-bit or 256-bit memory location, or to move data between two XMM or two YMM registers. When the source or destination operand is a memory operand, the operand must be aligned on a 16-byte (128-bit version) or 32-byte (VEX.256 encoded version) boundary or a general-protection exception (#GP) will be generated.

To move double-precision floating-point values to and from unaligned memory locations, use the (V)MOVUPD instruction.

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

128-bit versions: Moves 128 bits of packed double-precision floating-point values from the source operand (second operand) to the destination operand (first operand). This instruction can be used to load an XMM register from a 128-bit memory location, to store the contents of an XMM register into a 128-bit memory location, or to move data between two XMM registers. When the source or destination operand is a memory operand, the operand must be aligned on a 16-byte boundary or a general-protection exception (#GP) will be generated. To move single-precision floating-point values to and from unaligned memory locations, use the VMOVUPD instruction.

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 destination are zeroed.

VEX.256 encoded version: Moves 256 bits of packed double-precision floating-point values from the source operand (second operand) to the destination operand (first operand). This instruction can be used to load a YMM register from a 256-bit memory location, to store the contents of a YMM register into a 256-bit memory location, or to move data between two YMM registers. When the source or destination operand is a memory operand, the operand must be aligned on a 32-byte boundary or a general-protection exception (#GP) will be generated. To move single-precision floating-point values to and from unaligned memory locations, use the VMOVUPD instruc-tion.

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

Operation

MOVAPD (128-bit load- and register-copy- form Legacy SSE version)

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

(V)MOVAPD (128-bit store-form version)

DEST[127:0] ← SRC[127:0]

VMOVAPD (VEX.128 encoded version)

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

VMOVAPD (VEX.256 encoded version)

DEST[255:0] ← SRC[255:0]

Intel C/C++ Compiler Intrinsic Equivalent

MOVAPD:

__m128d _mm_load_pd (double const * p);

MOVAPD:

_mm_store_pd(double * p, __m128d a);

VMOVAPD:

__m256d _mm256_load_pd (double const * p);

VMOVAPD:

_mm256_store_pd(double * p, __m256d a);

SIMD Floating-Point Exceptions

None.

Other Exceptions

See Exceptions Type 1.SSE2; additionally