dest = source
The movupd instruction moves 2 double precision floating point values (64 bits each) from the source value (second operand) to the destination. The source and the destination can be an XMM register or a memory location. You can not use 2 memory addresses. The vmovupd instruction allows moving 4 doubles between YMM registers and memory.
This version does not require memory alignment. In the original designs movapd was faster than than movupd (move unaligned). When in doubt use movupd instead.
movupd moves the values without inspection or conversion.
An XMM register is 128 bits total, while CPUs supporting AVX instructions have an additional 128 bits in each register accessible as YMM registers.
movupd xmm1, xmm2 ; moves 2 doubles from xmm2 to xmm1 ; leaves the rest of xmm1 unchanged movupd xmm2, [x] ; moves 2 doubles from variable x to xmm2 ; leaves the rest of xmm2 alone movupd [y], xmm0 ; moves 2 doubles from xmm0 to variable y ; moves precisely 128 bits vmovupd xmm1, xmm2 ; moves 2 doubles from xmm2 to xmm1 ; leaves the rest of xmm1 unchanged vmovupd ymm1, ymm2 ; moves 4 doubles from ymm2 to ymm1 vmovupd ymm2, [x] ; moves 4 doubles from variable x to ymm2 vmovupd [y], ymm0 ; moves 4 doubles from ymm0 to variable y