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2016-01-21refactor internal atomic.hRich Felker-168/+0
rather than having each arch provide its own atomic.h, there is a new shared atomic.h in src/internal which pulls arch-specific definitions from arc/$(ARCH)/atomic_arch.h. the latter can be extremely minimal, defining only a_cas or new ll/sc type primitives which the shared atomic.h will use to construct everything else. this commit avoids making heavy changes to the individual archs' atomic implementations. definitions which are identical or near-identical to what the new shared atomic.h would produce have been removed, but otherwise the changes made are just hooking up the arch-specific files to the new infrastructure. major changes to take advantage of the new system will come in subsequent commits.
2015-05-19inline llsc atomics when building for sh4aBobby Bingham-0/+83
If we're building for sh4a, the compiler is already free to use instructions only available on sh4a, so we can do the same and inline the llsc atomics. If we're building for an older processor, we still do the same runtime atomics selection as before.
2014-10-10add explicit barrier operation to internal atomic.h APIRich Felker-1/+3
2014-08-25add working a_spin() atomic for non-x86 targetsRich Felker-0/+1
conceptually, a_spin needs to be at least a compiler barrier, so the compiler will not optimize out loops (and the load on each iteration) while spinning. it should also be a memory barrier, or the spinning thread might keep spinning without noticing stores from other threads, thus delaying for longer than it should. ideally, an optimal a_spin implementation that avoids unnecessary cache/memory contention should be chosen for each arch, but for now, the easiest thing is to perform a useless a_cas on the calling thread's stack.
2014-07-27clean up unused and inconsistent atomics in arch dirsRich Felker-5/+0
the a_cas_l, a_swap_l, a_swap_p, and a_store_l operations were probably used a long time ago when only i386 and x86_64 were supported. as other archs were added, support for them was inconsistent, and they are obviously not in use at present. having them around potentially confuses readers working on new ports, and the type-punning hacks and inconsistent use of types in their definitions is not a style I wish to perpetuate in the source tree, so removing them seems appropriate.
2014-02-27rename superh port to "sh" for consistencyRich Felker-0/+87
linux, gcc, etc. all use "sh" as the name for the superh arch. there was already some inconsistency internally in musl: the dynamic linker was searching for "ld-musl-sh.path" as its path file despite its own name being "ld-musl-superh.so.1". there was some sentiment in both directions as to how to resolve the inconsistency, but overall "sh" was favored.