[U-Boot-Users] [PATCH] Add call command on PPC

Mike Frysinger vapier at gentoo.org
Fri Feb 15 08:29:39 CET 2008


On Friday 15 February 2008, Haavard Skinnemoen wrote:
> Mike Frysinger <vapier at gentoo.org> wrote:
> > > if someone can tell me what the number of args are for each arch we
> > > can see about providing this everywhere.
> >
> > are you sure you actually need to worry about such things ?  i'm pretty
> > sure any relevant architecture says that the first X arguments go via
> > registers and the rest go on the stack.  let the compiler worry about the
> > exact value for X.
>
> I guess the real question is whether it's acceptable to pass arguments
> on the stack to such subprograms. If the answer is yes, why not simply
> use varargs?

if the goal is to keep things in registers, "call" and its description are way 
too vague.  the description makes me think this is meant to be a "go" for 
functions.

> If the answer is no: avr32 can pass up to 5 arguments through registers.

x86 does 0 while Blackfin does 3.
-mike
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