This time you are in need to download a small file to do your analysis. Fire it up in IDA Pro and tell me what is happening here? Remember: Something floating around…
Microsoft x64 calling convention
The x64 calling convention (for long mode on x86-64) takes advantage of additional register space in the AMD64/Intel 64 platform. The registers RCX, RDX, R8, R9 are used for integer and pointer arguments, and XMM0, XMM1, XMM2, XMM3 are used for floating point arguments.