Re: [Freemint-discuss] __M680x0__ macros in gcc 7 (was Re: [Freemint-list] Broken udelay() for m68000)

[David G. <dga...@gm...>]

2018-04-21 17:36 GMT+02:00 Thorsten Otto <ad...@th...>:
> On Samstag, 21. April 2018 17:15:38 CEST David Gálvez wrote:
>> I'm thinking about creating the machine flag "COLDFIRE" in KERNELDEFS,
>> add it in the sources wherever the M68040 macro is used and then
>> remove the -DM68040 flag when compiling the MINTV4E.PRG.
>
> It might depend. As Vincent pointed out, if you are using the same compiler
> flags for different targets, then you have to use some define in the Makefile
> (but i would prefer something else than M68000 since that might clash again).
> When it comes to distinguish between whether you can use code for a specific
> processor, you are better off using the compiler defined macros like
> __mcoldfire__. No need to add a separate define for this in the Makefile, that
> will makes things just more complicated than necessary, and again add
> confusion which macro to test.
>

OK I see, then I'll add __mcoldfire__ checks wherever M68040 is used,
remove -D68040 flag in MINTV4E.PRG build flags. and I won't create a
new COLDFIRE flag if it's not necessary.

> I think i already mentioned this, but you just have to keep in mind that -
> m68020-60 will define all macros from __mc68020__ upto __mc68060__, while -
> m68060 will *only* define __mc68060__, so there might be places that currently
> test for __mc68020__ only, where they actually want to know whether 68020 and
> above instructions can be used, and thus have to be changed to test for any of
> the macros.
>

Yes I think you did but I got confused by the old  __M680x0__  macro
behavior. Fortunately there aren't to many instances where __mc68020__
is used, the ones that I swapped in the commit and I've seen one in
the ext2 code that should be corrected for sure.

> But setting up the Makefile to use something like -mc68020 -DM68020 is imho
> confusing, and again you will have a mix of tests.

At the end creating the M68020 machine flag isn't necessary but I
think that the -D68000 when compiling MINT020.PRG should be removed,
I've searched for the commit where this was added and there is no
explanation about why -D68000 is needed in the 68020 kernels.