Re: [Arm] Remaining difference in crt0 code

Well, at first glance all the differences are related to semihosting v2.
I think Tamar can help me with that (if he doesn't mind). Especially I
do see his comment in
https://cygwin.com/git/gitweb.cgi?p=newlib-cygwin.git;a=commit;h=6d6a623e7d8eb9e521bdbd73a7eafdd482678cea

"This patch does this, I have not updated newlib/libc/* as that is
quite out of date already. A proper sync is needed in order to get
things back in sync.
A different patch for this would be best."
I can say time " The time has come" :)

Moreover Tamar has a commit rights so it can be done much faster.

Alex

On Mon, Apr 15, 2019 at 1:17 PM Alexander Fedotov <[email protected]> wrote:
>
> Ok, thanks.
>
> On Mon, Apr 15, 2019 at 12:14 PM Richard Earnshaw (lists)
> <[email protected]> wrote:
> >
> > On 12/04/2019 21:42, Alexander Fedotov wrote:
> > > Hello Richard
> > >
> > > There is still some difference in crt0.S code in libgloss and libc
> > > respectively. Could you help me figure out what version is correct so
> > > we can get rid of this.
> > >
> >
> > I don't think we can clean this up file at a time.  Trying to do so will
> > likely create inconsistencies in the sources as some files will be
> > patched and others not.
> >
> > "git blame" and "git show" will be your friends here... For example,
> > taking the first hunk:
> >
> > > Differences are following:
> > >
> > > --- newlib/libc/sys/arm/crt0.S    2019-04-12 23:28:32.237488800 +0300
> > > +++ libgloss/arm/crt0.S    2019-04-12 23:28:32.237488800 +0300
> > > @@ -79,6 +79,19 @@
> > >      .fnstart
> > >  #endif
> > >
> > > +    /* __ARM_ARCH_PROFILE is defined from GCC 4.8 onwards, however
> > > __ARM_ARCH_7A
> > > +    has been defined since 4.2 onwards, which is when v7-a support was added
> > > +    and hence 'A' profile support was added in the compiler.  Allow for this
> > > +    file to be built with older compilers.  We only call this for A profile
> > > +    cores.  */
> > > +#if defined (__ARM_ARCH_7A__) || (__ARM_ARCH_PROFILE == 'A')
> > > +/*  The init hook does not use the stack and is called before the
> > > stack has been set up.  */
> > > +#ifdef ARM_RDI_MONITOR
> > > +    bl    _rdimon_hw_init_hook
> > > +    .weak    FUNCTION (_rdimon_hw_init_hook)
> > > +#endif
> > > +#endif
> > > +
> >
> > "git blame" shows that this hunk is derived from two commits 99be2bc4ff
> > and then shortly afterwards 639951dda7.  "git show" can then be used to
> > view these individual patches and you can also use the date information
> > to identify the post to the newlib mailing list, which may contain
> > additional information about the patch.
> >
> > Unwinding all of this is going to be a bit tedious, I fear, so I really
> > appreciate any assistance you can give.
> >
> > R.