Re: RFA: rs6000: remove some uses of DEPRECATED_REGISTER_BYTE

[Kevin Buettner <kevinb at redhat dot com>]

On 21 May 2004 17:09:22 -0500
Jim Blandy <jimb@redhat.com> wrote:

> Kevin Buettner <kevinb@redhat.com> writes:
> 
> > On 20 May 2004 19:24:51 -0500
> > Jim Blandy <jimb@redhat.com> wrote:
> > 
> > > 2004-05-20  Jim Blandy  <jimb@redhat.com>
> > > 
> > > 	* rs6000-tdep.c (rs6000_push_dummy_call): Remove uses of
> > > 	DEPRECATED_REGISTER_BYTE and deprecated_registers.
> > 
> > Would you mind revising the patch to call convert_typed_floating()
> > for the floating point cases?  I think that will obviate the need
> > for some of the memset/memcpy calls.  (See ppc_sysv_abi_push_dummy_call()
> > in ppc-sysv-tdep.c.)
> > 
> > It looks okay otherwise...
> 
> So, wait, does this mean that the existing code like this is wrong?
> 
>       if (TYPE_CODE (type) == TYPE_CODE_FLT)
> 	{
> 
> 	  /* Floating point arguments are passed in fpr's, as well as gpr's.
> 	     There are 13 fpr's reserved for passing parameters. At this point
> 	     there is no way we would run out of them.  */
> 
> 	  if (len > 8)
> 	    printf_unfiltered ("Fatal Error: a floating point parameter "
>                                "#%d with a size > 8 is found!\n", argno);
> 
> 	  memcpy (&deprecated_registers[DEPRECATED_REGISTER_BYTE
>                                         (tdep->ppc_fp0_regnum + 1 + f_argno)],
> 		  VALUE_CONTENTS (arg),
> 		  len);
> 	  ++f_argno;
> 	}
> 
> This code takes a floating-point value, of whatever size, and just
> copies it into the left end of the floating-point register.  My PPC
> book says "Every instruction that interprets the contents of an FPR as
> a floating-point value uses the floating-point double format for this
> interpretation."
> 
> Calls to unprototyped functions would promote arguments to double
> anyway, so this isn't a big deal there, but it seems bogus for
> prototyped functions.

Sorry for taking so long on this one...

I'm okaying your original patch since it's a faithful conversion of
deprecated to non-deprecated code.  We can revisit the matter of
whether convert_typed_floating() should be used or not at a later
date.

Kevin