Re: [hatari-devel] DSP for Previous

[Thomas Huth <th.huth@xxxxxx>]

Am Fri, 03 Jul 2015 23:11:29 +0200
schrieb Nicolas Pomarède <npomarede@xxxxxxxxxxxx>:

> Le 03/07/2015 22:42, Andreas Grabher a écrit :
> >
> > Am 02.07.2015 um 20:39 schrieb Nicolas Pomarède
> > <npomarede@xxxxxxxxxxxx>:
> >
> >> Le 02/07/2015 20:28, Laurent Sallafranque a écrit :
> >>> Thanks a lot for this Andreas.
> >>> The problem is that I really have few time actually.
> >>> Maybe in september.
> >>>
> >>> Nicolas, I suggest we apply this patch after the new version of
> >>> hatari.
> >>>
> >>> Best regards
> >>> Laurent
> >>
> >> Yes, thanks a lot Andreas. I gave a look to the diff and this
> >> makes quite a lot of changes, so I agree it would be better to
> >> wait after 1.9 is released to apply some changes.
> >>
> >> 2 questions for andreas :
> >>
> >> - what are the difference with dsp in hatari ? Only interrupt
> >> handling or are there any other changes ? (I see DMA interrupts
> >> were added, IIRC it's missing in Hatari)
> >
> > I forgot to mention, that there are a few other changes. Some of
> > them might be useful, or just do no harm. Some of them are specific
> > to Previous and should not be merged. Almost all changes in dsp.c
> > are specific to Previous and should not be merged. The
> > NeXT-specific DSP memory map of course also should not be merged.
> > The changes to the host interface might be useful or at least do
> > not harm. If you only want the new interrupt system, then you
> > should have a look at commit 471 of Previous at
> > http://sourceforge.net/p/previous/code/commit_browser
> >
> > I tried to make a patch for Hatari, but i think it might be useful
> > to merge step by step. I can assist with that.
> >
> 
> Thanks I think laurent or me will come back to you later to merge
> this in Hatari (don't worry if this is not in the next weeks :) )
> 
> >>
> >> - also, why are some variables declared as 'volatile' ? This is
> >> usually when a variable holds the content of some hardware
> >> registers, but here it's not the case.
> >>
> >
> > To be honest, i did never use the volatile declaration before. I
> > just tried to match the existing code, which also included
> > volatiles.
> 
> I think you can remove them, IMO it always looks confusing to have 
> unneeded options when declaring variables.

The "volatiles" are likely a remainder from the times when the DSP run
in its own thread. But since this support has been removed quite a
while ago already, I think we could also remove the "volatiles" in
the DSP code of Hatari.

 Thomas