Re: Add memcpy support for SPARC

[Joel Sherrill <joel at rtems dot org>]

On Wed, May 30, 2018 at 11:40 AM, Gedare Bloom <gedare@rtems.org> wrote:

> On Thu, May 24, 2018 at 4:43 PM, Joel Sherrill <joel@rtems.org> wrote:
> > On Thu, May 24, 2018, 2:19 PM Eric Blake <eblake@redhat.com> wrote:
> >
> >> On 05/24/2018 02:09 PM, Aditya Upadhyay wrote:
> >> > Hi Developers,
> >> >
> >> > Is this ok to add memcpy implementation from Open Solaries?
> >> >
> >> >
> >> https://bitbucket.org/a3217055/illumos-gate-import/src/
> 741592a55c4c9746705ce0fd9232f5acded43ed0/usr/src/lib/libc/
> sparc/gen/memcpy.s?at=default&fileviewer=file-view-default
> >>
> >> That uses the CDDL license.  Nothing else in newlib does.
> >>
> >> The FSF claims CDDL and GPL are incompatible; others refute this claim
> >> (such as
> >>
> >> https://opensource.stackexchange.com/questions/
> 2094/are-cddl-and-gpl-really-incompatible),
> >>
> >> but I'm not a lawyer to say who is right.  At any rate, given the
> >> controversy, my gut feel is that you should NOT copy any CDDL code into
> >> newlib, unless YOU provide the lawyers to back up your claim.
> >>
>
> Regardless of the incompatibility question of CDDL with GPL, since
> CDDL is not used anywhere in newlib, it would seem wise to avoid it.
> (I don't trust any License that is longer than a page, regardless of
> what anyone's lawyer says.)
>
>
> >> > If yes, then Could you please tell us rules about modifying the
> >> > Licance of third party code?
> >>
> >> I _do_ know that you CANNOT modify the existing license on ANY file that
> >> you are importing from a third party, since you are not the license
> >> holder (some permissive licenses allow you to relicense code under a
> >> more restrictive license of your choice, which is different from
> >> modifying the existing license - but I doubt CDDL falls into that
> >> category).  And of course, using that code without copying the license
> >> statement is a bad idea.
> >>
> >> So that probably means using OpenSolaris code as your base point is a
> >> bad idea.
> >>
> >
> > Ok. Since you and Corinna disagree, let's be safe. Do you have another
> > source for an acceptablely licensed SPARC V7 mem* and str*?
> >
>
> My experience has been that netbsd has the best liberally licensed
> sparc-v7 code base among general purpose OS (outside of Sun
> derivatives). If you did not succeed there, you probably have to roll
> your own.
>

Is this the NetBSD source you would look at?

https://github.com/NetBSD/src/tree/netbsd-8/lib/libc/arch/sparc

I don't see any optimized string or memory methods.  Am I missing them?


Unless someone has a source for these methods to be merged from,
I do not think it is a good investment of Salil's GSoC time to implement
SPARC
mem* and str* methods. There are other missing POSIX methods and multiple
others could go from 0 to available versus these SPARC methods which are
present but sub-optimal.

OTOH I do see the fenv.h support methods which is a good thing
for that. :)




>
> Gedare
>