> On Oct 9, 2019, at 11:41 AM, Garrett D'Amore <garr...@damore.org> wrote: > > I don't think 32-bit compilers generally offer builtins for 64-bit atomics. > Frankly, they can't really unless the underlying ISA provides some additional > support for this in particular.
Yes, that is why the builtins exist... the underlying ISA may have a method that is not part of the C language. Worst case, mutex protection will work... slowly. -- richard > > To implement a 64-bit atomic on a 32-bit architecture, you generally needs > some additional state somewhere -- typically some sort of mutex or spinlock. > That has to live somewhere. (You *might* be able to have a compiler builtin > that provides this along with a compiler runtime which provides an instance > of the spinlock somewhere in the program's data section. I think this sort > of "builtin" (which isn't really builtin at all) generally can't be used in > operating system kernels -- e.g. with --freestanding.) >> On 10/9/2019 11:26:40 AM, Richard Elling <richard.ell...@richardelling.com> >> wrote: >> >> If it is possible to specify a compiler version, it might be easier to use >> the compiler >> builtin atomics. Just sayin' >> -- richard >> > > openzfs <https://openzfs.topicbox.com/latest> / openzfs-developer / see > discussions <https://openzfs.topicbox.com/groups/developer> + participants > <https://openzfs.topicbox.com/groups/developer/members> + delivery options > <https://openzfs.topicbox.com/groups/developer/subscription>Permalink > <https://openzfs.topicbox.com/groups/developer/T3ee8a81d5f09f2ec-Me9f5c4a72346d54fcfcd775f> ------------------------------------------ openzfs: openzfs-developer Permalink: https://openzfs.topicbox.com/groups/developer/T3ee8a81d5f09f2ec-M0e1652fa334ab713cd3c6235 Delivery options: https://openzfs.topicbox.com/groups/developer/subscription
