In the x86 assembly programming language, MOVAPD is the name for a specific action performable by modern x86 processors with 2nd-generation Streaming SIMD Extensions (SSE2). This action involves copying a pair of numbers to temporary space in the processor for use in other computations. MOVAPD is one of the fastest ways to accomplish this effect - it is faster than the comparable instruction MOVSD.
Specifically, MOVAPD causes a 16-byte-aligned packed-doubles source to be copied to an XMM register or a 16-byte memory region.
Usage Opcode Assembly (Intel syntax) Assembly (AT&T syntax) intrinsic equivalent(s) built-in(s) 66 0F 28 /r MOVAPD xmm1, xmm2/m128 MOVAPD xmm2/m128, xmm1 __m128 _mm_load_pd(double* p) 66 0F 29 /r MOVAPD xmm1/m128, xmm2 MOVAPD xmm2, xmm1/m128 void _mm_store_pd(double* p, __m128 a)
The source operand can be either an XMM register (xmm2) or a memory address (m128).
The destination operand can be either an XMM register (xmm1) or a memory address (m128). Note, however, that the source and destination operands cannot both be memory addresses.
Potential Exceptions If a memory address operand is not 16-byte-aligned, a general protection exception (#GP) will be raised. This can cause strange interoperability bugs when ordinary code calls an external code that was compiled with the assumption of a 16-byte-aligned stack frame boundary.
References documentation Intel 64 and IA-32 Architectures Optimization Reference Manual, November, 2006. Intel 64 and IA-32 Architectures Software Developer's Manual Volume 2A: Instruction Set Reference, A-M, November, 2006.
See also MOVAPS/MOVAPD MOVDDUP MOVHLPS MOVHPS/MOVHPD MOVLHPS MOVLPS/MOVLPD MOVMSKPS/MOVMSKPD MOVNTPS MOVSHDUP MOVSLDUP MOVSS/MOVSD MOVUPS/MOVUPD
x86 instruction listings