Sorry, it was asked before, couldn't find this in FAQ.

How 8 byte( double) parameters are passed to 'double' versions of OpenGL functions functions. Low 32 bit first, than high? Looking at C headers , it seems that they passed by value.
Posted on 2003-01-09 23:36:01 by Sergo
Push upper dword first, then the lower (x86 is little endian, the stack grows downward).
Posted on 2003-01-10 13:49:27 by Jan Wassenberg