On Tue, Feb 12, 2008 at 05:46:49AM +0800, Bean wrote:
> > > +_bsd_mod_CFLAGS = $(COMMON_CFLAGS)
> > > +_bsd_mod_LDFLAGS = $(COMMON_LDFLAGS)
> > > +
> > > +# For freebsd.mod
> > > +bsd_mod_SOURCES = loader/i386/pc/bsd_normal.c
> > > +bsd_mod_CFLAGS = $(COMMON_CFLAGS)
> > > +bsd_mod_LDFLAGS = $(COMMON_LDFLAGS)
> >
> > How much pc-dependant are those? Can we hope they will work in e.g.
> > i386-coreboot in the future, when *BSD kernels remove their BIOS
> > dependency?
>
> freebsd doesn't need bios at all, openbsd need the memory map, but i
> guess it's easy to construct one without using int 15.
In that case, loader/i386/ would be better than loader/i386/pc. Moving files
in CVS is painful ;-)
> > > +FUNCTION(grub_unix_real_boot)
> > > + call EXT_C(grub_dl_unload_all)
> > > + call EXT_C(grub_stop_floppy)
> > > +
> > > + cli
> > > +
> > > + popl %eax
> > > + popl %eax
> > > + call *%eax
> >
> > Why a call? Do we need the return address in the stack here? A comment
> > would
> > be nice in that case.
>
> bsds using stack to pass parameter, it's like this:
>
> void __cdecl (*func)(parm1, parm2,...);
>
> the first pop remove the return address, the second gets the address
> of func, and then call it. the function never returns, using call just
> make sure the first parameter is at esp + 4.
Ok. How about adding a comment to make this clear? Maybe something like:
/* Use cdecl calling convention for *BSD kernels. */
FUNCTION(grub_unix_real_boot)
....
/* Discard `grub_unix_real_boot' return address. */
popl %eax
/* Fetch `entry' address ... */
popl %eax
/* ... and put our return address in its place (the kernel will ignore
it, but it expects %esp to point to it. */
call *%eax
does this look good?
--
Robert Millan
<GPLv2> I know my rights; I want my phone call!
<DRM> What use is a phone call… if you are unable to speak?
(as seen on /.)
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