Re: ANN: Cortex GNAT RTS 20180419

[Jere <jhb.chat@gmail.com>]

On Sunday, April 29, 2018 at 7:51:02 AM UTC-4, Simon Wright wrote:
> Jere  writes:
> 
> > On Saturday, April 28, 2018 at 12:13:14 PM UTC-4, Simon Wright wrote:
> >> There are three parallel releases at Github[1], for
> >>
> >> * GNAT GPL 2016/GCC 6
> >> * GCC 7
> >> * GNAT GPL 2017
> >>
> >> (three, because of changes to the interface between the compiler and the
> >> RTS).
> >>
> >> There's not much user-visible change from the last GCC 7 release[2],
> >> except that all but 2k of free store is available for the heap (the 2k
> >> is used for startup and interrupt stack).
> >>
> >> [1] https://github.com/simonjwright/cortex-gnat-rts/releases
> >> [2] https://github.com/simonjwright/cortex-gnat-rts/releases/tag/r20171016
> >
> > Thank you so much for keeping these up to date.  Question:
> > Do you have any suggestions for pulling out a ZFP from this repo?  I know
> > it isn't setup for that, but was curious if you had any tips for what
> > to mainly look for.  I'm not so much worried about changing the ada files,
> > but I am more interested in what types of changes (if any) should I be
> > looking to do to the ld file, the gpr file, the xml file, etc.  So mostly
> > the build system.  I'm probably gonna try and mod the ardiuno one as it
> > is closest to my chip (an M0+).  Right now, I have been pulling from one
> > of your older revisions where the ZFP was still available.
> 
> One you haven't mentioned is system.ads.
> 
> The barebones site https://wiki.osdev.org/Ada_Bare_bones wants you to
> put the restrictions in gnat.adc; personally I've put them in
> system.ads, that way you don't need to worry about whether your own code
> will see the restrictions.
> 
> SNIPPED...
> 
> You could change this to do byte-by-byte copy (AdaCore's RTSs do this in
> assembly) but of course your own code (and even libgnat) might use the
> libc functions (Interfaces.C uses memcpy), and there is no way I can see
> to tell GCC not to do this.
> 
> Of course you could build your own, but I've got round this by using
> newlib. ISTR writing up how to build newlib for GNAT GPL, but where...?
> Anyway, I'm currently using newlib 2.5.0 and building as in [2]. I
> _think_ the gpl branch would do the job. FYI, newlib works out what cpu
> versions to build from the compiler capabilities, as reported by e.g.
> arm-eabi-gcc -print-multi-lib.
> 
> [1] https://docs.adacore.com/gnathie_ug-docs/html/gnathie_ug/gnathie_ug/using_gnat_pro_features_relevant_to_high_integrity.html#array-and-record-assignments-and-the-high-integrity-profiles
> [2] https://sourceforge.net/u/simonjwright/buildingarmeabi/code/ci/default/tree/

Thank you very much.  I currently supply the byte by byte copy.  I don't have 
any experience using newlib, but I'll take a look.  Thanks again for all your 
hard work.