[ldc, asm] Accessing function parameters in inline assembler

[Manuel König]

The problem is mostly solved now, objdump saved me :)

It turns out ldc passes 32-bit parameters in EDI, ESI and 64-bit
parameters in RDI, RSI. The result is in EAX or RAX, depending on the
size. The segfaults I encountered are caused by using ESP as
stackpointer, but in 64 bit mode this should of course have been RSP.

I think this solves all my practical problems for now, but it would be
nice to know the detailed calling conventions, or are they maybe
generated on-the-fly by llvm to get the best calling convention for
each single function? I also tried to enforce the documented D calling
convention with extern(D), and also tried extern(C), but that didn't
change anything.