| From: | Frank Wille |
| Date: | 07 Aug 2000 at 23:15:21 |
| Subject: | Re: morphos ;-) |
Oliver Roberts wrote:
> On 07-Aug-00 11:50:26 BST, Michael.Merkel wrote:
> > and why not going the "morphos way" by simply disabling the 68k
> > processor with the ability to let ppc native programs run at full
> > speed without those context switches? if i understand it right only
> > this would give the possibility to have a really fast system.
>
> This appears to be a common mis-conception, brought on by the MorphOS
> hype machine, I guess :) Until MorphOS contains a totally 68k free
> rendition of AmigaOS, MorphOS PPC apps will still not be able to run at
> "full" speed.
True. But they are already very fast, because many important parts
of AmigaOS are PPC-native.
> With MorphOS, PPC apps will still have to use 68k code (e.g.
> for disk/io)
MorphOS has a PPC-native cybppc.device, a PPC-native SFS file
system, and some important dos.library functions are PPC native,
so you have a good chance to run at full speed for disk/io.
> As I mentioned, 68060 users will probably notice the difference most,
> since the 68k emulation is not capable of the same speed. True, the
> native PPC apps will be fast, but what about all the existing software
> that is 68k only?
Good point. You're right, currently I wouldn't recommend running
existing 68k applications on MorphOS neither. But 68k applications
profit from the PPC-parts in the OS too (the whole exec.library is
PPC!). When a library function is ported to PPC, the 68k emulation
will run it directly. The system feels definitely faster than a
040/25.
> Why settle for the PPC only, when you can have a
> system which uses 68k and PPC processors side-by-side?
Because avoiding those nasty context-switches and cache con-
flicts? There are now a lot of buggy PPC programs out, because
not all programmers are completely aware of this problem.
> As an example,
> you can play mp3s on the PPC, and all your 68k software will still run
> at full speed.
Not at full speed. You still have only one system bus, which the
two CPUs have to share, even if there are no context switches. :)