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3-628 Vol. 2A MOVDQ2Q—Move Quadword from XMM to MMX Technology Register
INSTRUCTION SET REFERENCE, A-M
MOVDQ2Q—Move Quadword from XMM to MMX Technology Register
Description
Moves the low quadword from the source operand (second operand) to the destina-
tion operand (first operand). The source operand is an XMM register and the destina-
tion operand is an MMX technology register.
This instruction causes a transition from x87 FPU to MMX technology operation (that
is, the x87 FPU top-of-stack pointer is set to 0 and the x87 FPU tag word is set to all
0s [valid]). If this instruction is executed while an x87 FPU floating-point exception is
pending, the exception is handled before the MOVDQ2Q instruction is executed.
In 64-bit mode, use of the REX.R prefix permits this instruction to access additional
registers (XMM8-XMM15).
Operation
DEST ← SRC[63:0];
Intel C/C++ Compiler Intrinsic Equivalent
MOVDQ2Q __m64 _mm_movepi64_pi64 ( __m128i a)
SIMD Floating-Point Exceptions
None.
Protected Mode Exceptions
#NM If CR0.TS[bit 3] = 1.
#UD If CR0.EM[bit 2] = 1.
If CR4.OSFXSR[bit 9] = 0.
If CPUID.01H:EDX.SSE2[bit 26] = 0.
If the LOCK prefix is used.
#MF If there is a pending x87 FPU exception.
Real-Address Mode Exceptions
Same exceptions as in protected mode.
Opcode Instruction 64-Bit
Mode
Compat/
Leg Mode
Description
F2 0F D6 MOVDQ2Q mm, xmm Valid Valid Move low quadword from
xmm to mmx register.