"Theodore Y. Ts'o" <tytso@MIT.EDU> writes:
> (1 << OUT_FLAG_NUMBER) : 0") both involve an assembly language
> conditional jump instruction, which is expensive, because it involves
> pipeline stalls, etc.
Has it been measured ? I know that branch prediction is not 100%, but
I'm just trying to make sure we're not trying to solve a non-problem (if the
prediction works well, then the jump costs 0 (zero) cycles).
Branch prediction works in conditional testing when branching out of
loops. In the cases where you'd use copy_bit(), it isn't in a loop
condition, and yes it matters.
- Ted