GDC guys, can this toolchain support D?

[Iain Buclaw via Digitalmars-d]

On 11 January 2017 at 02:40, Manu via Digitalmars-d
<digitalmars-d at puremagic.com> wrote:
> On 10 January 2017 at 19:04, Iain Buclaw via Digitalmars-d
> <digitalmars-d at puremagic.com> wrote:
>>
>> On 10 January 2017 at 09:22, Manu via Digitalmars-d
>> <digitalmars-d at puremagic.com> wrote:
>> > Can any of the GDC guys comment on how difficult it would be to get this
>> > toolchain build script to include building GDC?
>> >
>> > https://github.com/SaturnSDK/Saturn-SDK-GCC-SH2
>> >
>> > I have a mate who's hacking on the Saturn and wants to build one of my
>> > projects.
>> > It'd be a really great test for embedded D; fairly small realtime
>> > target. I
>> > expect binary size to be a problem ;)
>>
>> Debian already has builds for SH4, there's just no druntime support.
>
>
> Cool. Obviously, this is an SH2 toolchain, and it's baremetal, not linux.
> Not sure what c-runtime it uses, but probably not glibc.
>
>> https://goo.gl/dznZIF
>>
>> But getting druntime working on it should be trivial enough.
>
>
> I'm looking for just the BetterC experience, but druntime still seems
> somewhat necessary... what parts need to be implemented for BetterC to work
> well?
>
>> - Fix core.stdc.* to handle the arch-specific bits for SH (just copy
>> from C headers).
>> - There's threadasm.S if you want to implement native fiber support,
>> otherwise you can fall back to ucontext_t.
>
>
> I expect existing SH4 code should be mostly compatible, and a good
> headstart.
> Doesn't sound too bad. I'm not using fibers though.
>
>> Does double == float on this platform?  That might be interesting...
>
>
> I think SH2 supports double, but it would be terminally slow... Is there a
> way to force double == float? What would that do to D?

Looking at the -march configurations, compile with the
-m2a-single-only flag.  I don't think it would affect the compiler in
any way, but I can't test that on compiler explorer because the sh4
compiler was built only to support sh4 and sh4-no-fpu.

You can play around with -m4-no-fpu here:

https://goo.gl/0vmt9v

I expect there to be no surprises unless you try to import anything.