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

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

2018-02-19 10:02 GMT+01:00 David Gálvez <dga...@gm...>:
> 2018-02-19 9:45 GMT+01:00 David Gálvez <dga...@gm...>:
>> Move this discussion from github to the list.
>>
>> So if I understand correctly __M680x0__ (with uppercase) is MiNT's
>> specific and it's deprecated, I've seen 7 use instances in the
>> kernel's code, by coincidence 4 in files I'm working with right now,
>> then the alternative is the compiler general  __mc680x0__ (with lower
>> case), but it's still no clear to me what is state of these macros in
>> gcc 7. Can use them safely?
>>
>>
>
> I have just read this in the gcc 7.3.0 manual:
>
> "GCC defines the macros __mcarch and __mcarch__ when tuning for 680x0
> architecture arch. It also defines mcarch unless either -ansi or a
> non-GNU -std option is used. If GCC is tuning for a range of
> architectures, as selected by -mtune=68020-40 or -mtune=68020-60, it
> defines the macros for every architecture in the range."
>
> So  in theory it's safe and nothing has been changed regarding these
> macros between compiler's version.
>
> I'm going to remove what is left of the uppercase macros and swap them
> by the lowercase ones
>

I've now replaced the old MiNT's specific macros by the generic ones.
I've left untouched the M680x0 macros (without underscores) that are
defined during the compile's time (see KERNELDEFS).
Those seems to have some extra purpose, for example the macro M68040
is defined when compiling the ColdFire kernel.

Still there are some defines that mix both macros types (like this one
 "#if !(defined(M68000) || defined(__mcoldfire__))")
https://github.com/freemint/freemint/blob/1196c6f665b6eed314b419ce560f445ebaeae5a1/sys/arch/intr.S#L749
If this is not on purpose we could replace them too for code consistency.