ThreadSetIterator::next comment #4006
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apfitzge
commented
Dec 7, 2024
| // Example (with 4 bits): | ||
| // self.0 = 0b1010 // initial value | ||
| // self.0 - 1 = 0b1001 // all bits at or after the lowest set bit are flipped | ||
| // 0b1010 & 0b1001 = 0b1000 // the lowest bit has been cleared | ||
| self.0 &= self.0 - 1; |
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Could expand comment to state that this is possibly faster than the slightly more clear bit-clearing:
self.0 ^= 1 << thread_id;but comes down to instruction pipelining since self.0-1 doesn't depend sequentially on thread_id. And I think probably more important to just document why this works in the first place.
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Problem
self.0 &= self.0 - 1, while common, is admittedly not that clearSummary of Changes
ThreadSetIterator::nextto make it clear why this worksFixes #