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Merge pull request #278 from slingamn/bitset_again 

simplify CAS logic a bit
This commit is contained in:
Daniel Oaks 2018-07-12 20:05:26 +10:00 committed by GitHub
parent 6ba741814d 318da22448
commit 1a5db02236
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1 changed files with 3 additions and 5 deletions
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8
irc/utils/bitset.go
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@ -37,17 +37,15 @@ func BitsetSet(set []uint64, position uint, on bool) (changed bool) {
mask = 1 << bit mask = 1 << bit
for { for {
current := atomic.LoadUint64(addr) current := atomic.LoadUint64(addr)
previouslyOn := (current & mask) != 0
if on == previouslyOn {
return false
}
var desired uint64 var desired uint64
if on { if on {
desired = current | mask desired = current | mask
} else { } else {
desired = current & (^mask) desired = current & (^mask)
} }
if atomic.CompareAndSwapUint64(addr, current, desired) { if current == desired {
return false
} else if atomic.CompareAndSwapUint64(addr, current, desired) {
return true return true
} }
} }