New primitive types?

[David Feuer]

Atomic operations, or the lack thereof, don't seem terribly relevant to immutable Haskell constructor fields.


David FeuerWell-Typed, LLP
-------- Original message --------From: Carter Schonwald <carter.schonwald at gmail.com> Date: 8/26/17  10:56 PM  (GMT-05:00) To: Florian Weimer <fw at deneb.enyo.de>, Michal Terepeta <michal.terepeta at gmail.com> Cc: ghc-devs <ghc-devs at haskell.org> Subject: Re: New primitive types? 
Which architectures are which?

I assume you mean the dec alpha allowed atomic operations on bytes... but
your phrasing is a teeny bit unclear

On Sat, Aug 19, 2017 at 4:34 AM Florian Weimer <fw at deneb.enyo.de> wrote:

> * Michal Terepeta:
>
> > On Tue, Aug 1, 2017 at 8:08 PM Carter Schonwald <
> carter.schonwald at gmail.com>
> > wrote:
> >> One issue with packed fields is that on many architectures you can't
> > quite do subword reads or
> >> writes.  So it might not always be a win.
> >
> > Could you give any examples?
>
> Historic DEC Alpha, now long obsolete.
>
> It is very hard to create compliant and performant implementations of
> Java 5, C 11 or C++ 11 on such architectures.  All these languages
> (and their subsequent revisions) require that naturally aligned
> objects can be accessed independently.  For example, you can't use a
> simple read-modify-write cycle to implement a single-byte store using
> word operations.
>
> That's why such architectures really do not have a future (or even a
> present), except maybe in niche markets such as GPGPU (but even there,
> things are heading towards the de-facto standard memory model).
>
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