Age | Commit message (Collapse) | Author | Lines | |
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2016-01-23 | improve aarch64 atomics | Rich Felker | -16/+36 | |
aarch64 provides ll/sc variants with acquire/release memory order, freeing us from the need to have full barriers both before and after the ll/sc operation. previously they were not used because the a_cas can fail without performing a_sc, in which case half of the barrier would be omitted. instead, define a custom version of a_cas for aarch64 which uses a_barrier explicitly when aborting the cas operation. aside from cas, other operations built on top of ll/sc are not affected since they never abort but rather loop until they succeed. a split ll/sc version of the pointer-sized a_cas_p is also introduced using the same technique. patch by Szabolcs Nagy. | ||||
2016-01-21 | overhaul aarch64 atomics for new atomics framework | Rich Felker | -174/+25 | |
2016-01-21 | refactor internal atomic.h | Rich Felker | -0/+202 | |
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. |