Re: [m68k] Convert CPP_SPEC to TARGET_CPU_CPP_BUILTINS

[Bernardo Innocenti <bernie at develer dot com>]

Gunther Nikl wrote:
> On Sun, Sep 14, 2003 at 10:35:17PM +0200, Bernardo Innocenti wrote:
>
> > +	builtin_define_std ("mc68000");		\
> > +	if (TARGET_68020)			\
> > +	  {					\
> > +	    builtin_define_std ("mc68020");	\
> > +	    builtin_define_std ("mc68030");	\
> > +	  }					\
>
>   Its true that -m68030 is a synonym for -m68020 with GCC. However, defining
>   mc68030 together with mc68020 changes previous behaviour. mc68030 was only
>   defined through the specsfile when -m68030 was really specified on the
>   commandline.

I know, but there's no easy way to recover this information at this time.
Because the 68030 looks exactly like a 68020 except for the cache size,
the compiler doesn't care and user code should care even less.

To get that right, we would have to add dummy MASK_68030 and
TARGET_68030 macros just for that porpose.

> > +	if (TARGET_68040 || TARGET_68040_ONLY)	\
> > +	  builtin_define_std ("mc68040");	\
>
>   I think that TARGET_68040 is enough.

Hmmm... not if we want -m68060 to also define __mc68040__:

{ "68060", (MASK_68020|MASK_68881|MASK_BITFIELD
           |MASK_68040_ONLY|MASK_68060), "" },


But wait, the old behavior was to define just __mc68060__
in that case.

This is probably done because the 68060 lacks some 68040 FPU
instructions (and if I remember correctly, perhaps even some
integer ones such as CHK2).

Ok, I'll change it back to TARGET_68040 only.


> > +	if (TARGET_68881)			\
> > +	  builtin_define ("__HAVE_68881__");	\
>
>   This is also a change in behaviour if soft-float was default. TARGET_68881
>   is also true when -m680[46]0 was specified on the commandline.

This behavior should still hold:

   { "68881", MASK_68881, "" },

-m68881 adds the MASK_68881 flag.

   { "soft-float", - (MASK_68040_ONLY|MASK_68881),

-msoft-float removes the MASK_68881 flag.

   { "68020-40", (MASK_BITFIELD|MASK_68881|MASK_68020|MASK_68040), ""},
   { "68020-60", (MASK_BITFIELD|MASK_68881|MASK_68020|MASK_68040
                  |MASK_68060), "" },

These include MASK_68881 as well.


   { "68030", - (MASK_ALL_CF_BITS|MASK_68060|MASK_68040|MASK_68040_ONLY),
     N_("Generate code for a 68030") },
   { "68030", (MASK_68020|MASK_BITFIELD), "" },

Oddly, this doesn't...


   { "68040", - (MASK_ALL_CF_BITS|MASK_68060),
     N_("Generate code for a 68040") },
   { "68040", (MASK_68020|MASK_68881|MASK_BITFIELD
               |MASK_68040_ONLY|MASK_68040), "" },
   { "68060", - (MASK_ALL_CF_BITS|MASK_68040),
   { "68060", (MASK_68020|MASK_68881|MASK_BITFIELD
               |MASK_68040_ONLY|MASK_68060), "" },

... and these do :-)


> > +	if (TARGET_CPU32)			\
> > +	  {					\
> > +	    builtin_define_std ("mc68332");	\
> > +	    builtin_define_std ("mcpu32");	\
> > +	  }					\
>
>   I believe that will also change the behaviour because TARGET_CPU32 is
>   "TARGET_68020 && !TARGET_BITFIELD" which you can also get without
>   specifying -mcpu32.

No, you can't:

 { { "68020", - (MASK_ALL_CF_BITS|MASK_68060|MASK_68040|MASK_68040_ONLY),
     N_("Generate code for a 68020") },
   { "c68020", - (MASK_ALL_CF_BITS|MASK_68060|MASK_68040|MASK_68040_ONLY),
     N_("Generate code for a 68020") },
   { "68020", (MASK_68020|MASK_BITFIELD), "" },
   { "c68020", (MASK_68020|MASK_BITFIELD), "" },


> > +	if (flag_pic)				\
> > +	  {					\
> > +	    builtin_define ("__PIC__");		\
> > +	    builtin_define ("__pic__");		\
> > +	  }					\
>
>   Shouldn't these defined depending an the specific flag_pic value?

That's right, but I noticed all other back-ends just
define both symbols without caring at all... I thought
it was odd, but there has to be a reason.

--
 // Bernardo Innocenti - Develer S.r.l., R&D dept.
\X/  http://www.develer.com/

Please don't send Word attachments - http://www.gnu.org/philosophy/no-word-attachments.html