Re: [MiNT] PML trouble with -m68020-60

[Peter Slegg <p.slegg@scubadivers.co.uk>]

On Thu, 13 Jan 2011 22:20:01 , Vincent Rivière <vincent.riviere@freesbee.fr> wrote:
> Vincent Rivière wrote:
> > I noticed these problems last year when compiling POV-Ray. The 68000 an
> d
> > ColdFire versions worked well (return to d0/d1), while the -m68020-60
> > produced almost black pictures. I think it is a good testcase :-)
>
> I have patched PML to match the current GCC behavior with -m68020-60, I
> believe I did it right... but the result is still wrong.
>
> Then I have discovered something surprising... PML uses some math support
>
> functions provided by the MiNTLib, such as ldexp().
>
> And the MiNTLib is wrong for 2 reasons :
> - it tests the wrong define for detecting the FPU presence
> - when the FPU is present, it returns to d0/d1 instead of fp0
>
> Also, when compiling with -m68020-60:
> - GCC 2.95.3 sets __M68881__
> - GCC 4.x sets __HAVE_68881__
>
> Big mess.
> I'm going to more tests and provide patches, but this will take time.
>

This is a great discovery, I wonder what bugs have been caused by this.

Peter