Re: Using System.Machine_Code in GPL 2017 Zfp for Arm

[Simon Wright <simon@pushface.org>]

ahlan@marriott.org writes:

> We are trying to build a zfp system for an arm M3 processor that is
> not on the list of supported GPL processors.
> We only want the Ada intrinsics. We do not need or want any RTS and so
> expected that --RTS=zfp would do the trick.
> however when we place this switch on arm-eabi-gcc from GPL 2017 we get
> the error message
> RTS path not valid: Missing adainclude and adalib directories.
> So things are not as simple as we thought.
> It appears that --RTS takes the name of a directory so we created one
> and named this on the RTS switch.
> In the directory we placed two files ada_object_path and
> ada_source_path that both contain the single word gnat.

I'd expect ada_object_path to contain the word adalib, and adalib/ to
contain the .ali's and .a(s), or perhaps .o's. Don't know what happens
if you put them in gnat/ with the sources, but it seems to work for you!
(and you shouldn't need adalib/ at all - though the
compiler/gnatls/gprconfig rules for determining whether this looks
enough like an RTS are a bit arbitrary & changeable & not necessarily
consistent).

> In the RTS directory we then created the empty directory adalib and
> another directory gnat and placed in gnat directory the file
> System.ads which we copied from an RTS directory of a similar
> processor.
> This all seems to work.
> With this we are able to create simple programs.
> However when we want to use System.Machine_Code we get the error message that
> System.Machine_Code is not a predefined library.
> I suspect that we need to add something to our RTS directory.

You need s-maccod.ads (from the same place; looks pretty
machine-independent).

GNAT GPL 2017 has $prefix/arm-eabi/lib/gnat/zfp-lm3s which is an M3 system.