Rich Felker
513c043694
previously powerpc had a_cas defined in terms of its native ll/sc style operations, but all other atomics were defined in terms of a_cas. instead define a_ll and a_sc so the compiler can generate optimized versions of all the atomic ops and perform better inlining of a_cas. extracting the result of the sc (stwcx.) instruction is rather awkward because it's natively stored in a condition flag, which is not representable in inline asm. but even with this limitation the new code still seems significantly better.
musl libc
musl, pronounced like the word "mussel", is an MIT-licensed
implementation of the standard C library targetting the Linux syscall
API, suitable for use in a wide range of deployment environments. musl
offers efficient static and dynamic linking support, lightweight code
and low runtime overhead, strong fail-safe guarantees under correct
usage, and correctness in the sense of standards conformance and
safety. musl is built on the principle that these goals are best
achieved through simple code that is easy to understand and maintain.
The 1.1 release series for musl features coverage for all interfaces
defined in ISO C99 and POSIX 2008 base, along with a number of
non-standardized interfaces for compatibility with Linux, BSD, and
glibc functionality.
For basic installation instructions, see the included INSTALL file.
Information on full musl-targeted compiler toolchains, system
bootstrapping, and Linux distributions built on musl can be found on
the project website:
http://www.musl-libc.org/