Mobile is the new PC and AArch64 is the new x64

[Iain Buclaw]

On 12 September 2018 at 10:09, Joakim via Digitalmars-d
<digitalmars-d at puremagic.com> wrote:
> On Tuesday, 11 September 2018 at 16:50:33 UTC, Dejan Lekic wrote:
>>
>> On Monday, 10 September 2018 at 13:43:46 UTC, Joakim wrote:
>>>
>>> LDC recently added a linux/AArch64 CI for both its main branches and
>>> 64-bit ARM, ie AArch64, builds have been put out for both linux and Android.
>>> It does not seem that many are paying attention to this sea change that is
>>> going on with computing though, so let me lay out some evidence. ...
>>
>>
>> I mostly agree with you, Joakim. I own a very nice (but now old) ODROID U2
>> (check the ODROID XU4 or C2!) so ARM support is important for me...
>>
>> Also, check this:
>> https://www.hardkernel.com/main/products/prdt_info.php?g_code=G152875062626
>>
>> HOWEVER, I think Iain is right - PPC64 and RISC-V are becoming more and
>> more popular nowadays and may become more popular than ARM in the future but
>> that future is unclear.
>
>
> If and when they do, I'm sure D and other languages will be ported to them,
> but right now they're most definitely not.
>
> I know because I actually looked for a RISC-V VPS on which to port ldc and
> found nothing. Conversely, I was able to rent out an ARM Cubieboard2
> remotely four years back when I was first getting ldc going on ARM:
>
> https://forum.dlang.org/post/steigfwkywotxsyppvza@forum.dlang.org
>
> I contacted one of the few companies putting out RISC-V dev boards, Sifive,
> a couple weeks ago with the suggestion of making available a paid RISC-V
> VPS, and one of their field engineers got back to me last week with a note
> that they're looking into it.
>
> I think their model of having an open ISA with proprietary extensions will
> inevitably win out for hardware, just as a similar model has basically won
> already for software, but that doesn't mean that RISC-V will be the one to
> do it. Someone else might execute that model better.
>

POWER9 has been making some headway, for instance finally they have a
sensible real type (IEEE Quadruple).  Though the developers working on
glibc support seem to be making a shambles of it, where they want to
support both new and old long double types at the same time at
run-time!  It seems that no one thought about Fortran, Ada, or D when
it came to long double support in the C runtime library *sigh*.

For us, I think we can choose to ignore the old IBM 128-bit float, and
so remove any supporting code from our library, focusing instead only
on completing IEEE 128-bit float support (LDC, upstream your local
patches before i start naming and shaming you).

ARM seems to be taking RISC-V seriously at least (this site was taken
down after a couple days if I understand right:
http://archive.fo/SkiH0).  There is currently a lot of investment
going into ARM64 in the server space right now, but signals I'm
getting from people working on those projects are that it just doesn't
hold water.  With one comparison being a high end ARM64 server is no
better than a cheap laptop bought 5 years ago.

RISC-V got accepted into gcc-7, and runtime made it into glibc 2.27,
there's certainly a lot effort being pushed for it.  They have
excellent simulator support on qemu, porting druntime only took two
days.  Patches for RISCV64 will come soon, probably with some
de-duplication of large blocks.

Iain.