Re: [PATCH] oops_in_progress is unlikely()

[Jamie Lokier]

Richard B. Johnson wrote:
> 		cmpl	$1, %eax
> 		jz	1f
> 		jc	2f
> 		call	do_default
> 		jmp	more_code
> 	1:	call	do_something_if_equal
> 		jmp	more_code
> 	2:	call	do_something_if_less
> 	more_code:
> 
> In every case, one has to jump around code for other execution paths
> except the last, where you have to jump on condition anyway. There
> is no free liunch, and the straight-through route, do_default
> uas just as many jumps as the last.

Here is your code optimised for no jumps in the "do_default" case:

		cmpl	$1,%eax
		jbe	1f
		call	do_default
	more_code:
		.subsection 1
	1:	jnz	2f
		call	do_something_if_equal
		jmp	more_code
	2:	call	do_something_if_less
		jmp	more_code
		.previous

> > How would you optimise it, if you were writing assembly language yourself?

> I did. And I do this for a living. And, after 30 years of this shit
> they still haven't fired me. Learn something. I'm pissed.

It's ok to be pissed.  I'd be pissed too :)

*ducks*

Enjoy :)
-- Jame
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