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Vol. 2A 3-623
INSTRUCTION SET REFERENCE, A-M
MOVDQA—Move Aligned Double Quadword
MOVDQA—Move Aligned Double Quadword
Description
Moves a double quadword from the source operand (second operand) to the destina-
tion 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 a double quadword to or from unaligned memory locations, use the
MOVDQU instruction.
In 64-bit mode, use of the REX.R prefix permits this instruction to access additional
registers (XMM8-XMM15).
Operation
DEST ← SRC;
(* #GP if SRC or DEST unaligned memory operand *)
Intel C/C++ Compiler Intrinsic Equivalent
MOVDQA __m128i _mm_load_si128 ( __m128i *p)
MOVDQA void _mm_store_si128 ( __m128i *p, __m128i a)
SIMD Floating-Point Exceptions
None.
Protected Mode Exceptions
#PF(fault-code) If a page fault occurs.
#GP(0) If a memory operand effective address is outside the CS, DS,
ES, FS, or GS segment limit.
If a memory operand is not aligned on a 16-byte boundary,
regardless of segment.
Opcode Instruction 64-Bit
Mode
Compat/
Leg Mode
Description
66 0F 6F /r MOVDQA xmm1,
xmm2/m128
Valid Valid Move aligned double quadword
from xmm2/m128 to xmm1.
66 0F 7F /r MOVDQA xmm2/m128,
xmm1
Valid Valid Move aligned double quadword
from xmm1 to xmm2/m128.