x86 and PowerPC ABIs and Calling Conventions

[Nathan Binkert <binkertn_(_at_)_umich_(_dot_)_edu>]

Hi.  I am looking into rewriting some C code in assembly and I would like
if anyone can give me some pointers to where I can find calling convention
information so that I may call these ASM functions from C.  I can look
through the source, but I would really like some documentation if there is
any. I am most interested in how data is passed on the stack as a
parameters and what other information is placed on the stack, e.g. return 
address, etc.

Also, if anyone has a pointer where I can find out how the __asm__
directive works, I would appreciate that as well.


Thanks,
  Nathan Binkert