Alex Crichton 9c4e418fe0 Add a x86_64::cmpxchg16b intrinsic ...

This intrinsic isn't actually specified by Intel, but it's something
gated with CPUID and can otherwise be a useful thing to have when
building primitives!

There exists an `AtomicU128` type in the standard library but it's only
exposed currently (and it's unstable) when a platform fully supports
128-bit atomics. The x86_64 architecture does not support it *unless*
the `cmpxchg16b` instruction is available, and it isn't always available!

This commit is also a proposal for how we can include support for
128-bit atomics in the standard library on relevant platforms. I'm
thinking that we'll expose this one low-level intrinsic in
`std::arch::x86_64`, and then if desired a crate on crates.io can build
`AtomicU128` from this API.

In any case this is all unstable regardless!

2019-01-02 16:55:53 +01:00

..

src

Add a x86_64::cmpxchg16b intrinsic

2019-01-02 16:55:53 +01:00

Cargo.toml

fix _mm_castsi128_pd and _mm_castpd_si128 impls (#581)

2018-10-23 18:10:54 +02:00