* Michal Terepeta: > On Tue, Aug 1, 2017 at 8:08 PM Carter Schonwald <[email protected]> > 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 [email protected] http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
