Re: [rfa] mips argument passing fixes for o32

[Daniel Jacobowitz <dmj+ at andrew dot cmu dot edu>]

On Thu, Jul 12, 2001 at 03:44:18AM -0400, Andrew Cagney wrote:
> > These are based on testsuite failures (call-*-st, if I remember correctly)
> > and reading the argument passing code in GCC.  The struct alignment fix
> > definitely agrees with the ABI, though it's not always clear on this point -
> > it becomes necessary for us when the return value is a struct and thus there
> > is a hidden pointer as the first argument.  The shift fix matches this
> > comment in GCC and is not really specified by the ABI document:
> 
> 
> I get the feeling that these two changes fix two separate bugs:
> 
> 	o	botched struct parameter pass
> 
> 	o	botched struct return

Actually, they're both struct parameter passing.  But yes, two separate
bugs.

> Looking at just the first one:
> 
> > +	  /* Structures should be aligned to eight bytes (even arg registers)
> > +	     on MIPS_ABI_O32 if their first member has double precision. */
> > +	  if (gdbarch_tdep (current_gdbarch)->mips_abi == MIPS_ABI_O32
> > +	      && mips_type_needs_double_align (arg_type))
> > +	    {
> > +	      argreg += argreg & 1;
> > +	    }
> 
> this is approved.  However could you please change the expression:

> to something like:
> 
> 
> 	if ((argreg & 1))
> 	  argreg++;

Changed, and committed.  Thanks.

> your original expression makes my head hurt :-)

Got it from GCC :)

-- 
Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer