Role of edi/ebx during INTERNAL_SYSCALL

[Gaurav Mogre]

Hello,
I've just recently tried to look around the libC code, and I'm just a
bit confused on a few questions on INTERNAL_SYSCALL()   (for i386 via
sysenter mechanism): If nr=3 (which is the case for __execve),
LOADARGS_3 basically exchanges ebx and edi. I was wondering, why is it
that the args are actually loaded into either edi and ebx? In general,
how and when is the value of "args" stored in ebi
I was also wondering where are the elf auxillary vectors actually
parsed by libC into the TCB. I'm not really sure which functions call
in the .ctors segment.

Sorry if the questions are silly. I've just recently started looking
into libC and linux in general.

Regards,
Gaurav