On Mon, Jul 01, 2013 at 07:30:14AM -0700, H. Peter Anvin wrote:
> Unconditional branches don't need prediction. The branch predictor
> is used for conditional branches and in some hardware designs for
> indirect branches. Unconditional direct branches never go through
> the branch predictor simply because the front end can know with 100%
> certainty where the flow of control will be.
I meant the conditional Jcc branches:
ffffffff81774920 <mutex_lock>:
...
ffffffff8177492d: f0 ff 0b lock decl (%rbx)
ffffffff81774930: 79 08 jns ffffffff8177493a
<mutex_lock+0x1a>
ffffffff81774730 <mutex_unlock>:
...
ffffffff81774738: f0 ff 07 lock incl (%rdi)
ffffffff8177473b: 7f 0a jg ffffffff81774747
<mutex_unlock+0x17>
--
Regards/Gruss,
Boris.
Sent from a fat crate under my desk. Formatting is fine.
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