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.schonw...@gmail.com> Date: 8/26/17 10:56 PM (GMT-05:00) To: Florian Weimer <f...@deneb.enyo.de>, Michal Terepeta <michal.terep...@gmail.com> Cc: ghc-devs <ghc-devs@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 <f...@deneb.enyo.de> wrote: > * Michal Terepeta: > > > On Tue, Aug 1, 2017 at 8:08 PM Carter Schonwald < > carter.schonw...@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). >
_______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
