Question

Is there any faster method to store two x86 32 bit registers in one 128 bit xmm register?

movd  xmm0, edx
movd  xmm1, eax
pshufd xmm0, xmm0, $1
por   xmm0, xmm1 

So if EAX is 0x12345678 and EDX is 0x87654321, the result in xmm0 must be 0x8765432112345678.

Answer 1

With SSE 4.1 you can use movd xmm0, eax / pinsrd xmm0, edx, 1 and do it in 2 instructions.

For older CPUs you can use 2 x movd and then punpckldq for a total of 3 instructions:

movd xmm0, edx
movd xmm1, eax
punpckldq xmm0, xmm1