On 1/15/2018 11:31 AM, Segher Boessenkool wrote:
On Mon, Jan 15, 2018 at 01:39:43PM +0100, Sebastian Huber wrote:
On 13/01/18 00:16, Jeff Law wrote:
On 01/12/2018 04:07 PM, Joseph Myers wrote:
On Fri, 12 Jan 2018, Jeff Law wrote:
I was going to suggest deprecation for gcc-8 given how badly it was
broken in gcc-7 and the lack of maintenance on the target.
While we're considering deprecations, what happened to the idea of setting
a timescale by which cc0 targets need to be converted away from cc0 or be
removed?
I don't think we ever really hashed through what that might look like.
I'd be comfortable saying gcc-8 is the deprecation point. I know some
folks won't like that (someone already said so WRT the m68k, but didn't
step up to do the conversion), but I think that unless we set a point
nothing is likely to happen.
How much work is it to convert the m68k to LRA. Is this person days,
weeks, months or years?
Converting m68k to cc0 is a daunting task. This is a prerequisite to
enabling LRA, as mentioned.
I don't know if the Coldfire changes things but my recollection is that
all the m68xxx instructions you expect to modify %sr do so. That
doesn't make the task smaller but at least the m68k proper is simpler
CISC as described in the linked page.
As Sandra says, switching to LRA is easy in principle, and for simple
targets that is all really. For more complex and unusual targets you
run into situations LRA does not yet handle. Also, debugging LRA is
its own set of skills.
I know the m68k is an ugly beast with many years of architectural
evolution from m68000 to m68060 and then all the Coldfire variants.
It is one of the machine description files[1]. And I don't think there
are free simulators already in use for testing it.
But I **think** Sebastian is trying to figure out if this is something
he can do or if we (RTEMS, GCC, etc communities) can fund from m68k
and Coldfire users. Assuming this discussion isn't enough to chase
the embedded users to another architecture. Old school folks keeping
Amiga alive are a different animal
Is cc0 conversion enough to get m68k off the chopping block?
[1] Interestingly, the sparc, arm, powerpcspe, rs6000, and i386 are
all larger .md files. The i386 is 2.5 times larger.
--joel
Segher