[plug] Chat

[David Cambell]

> My completely un-informed understanding is that there's a bunch of the
> absolute base-kernel that is written with in-line asm
> for performance reasons, but  that as soon as you get out beyond a fairly
> narrow level beyond the kernel it's all pure C....
> is this the correct understanding?

asm code is used there and areas where every CPU cycle counts. These days it
is becoming less prevalent because:

	a) asm code is not portable (asm when there were only one or two CPUs
	   worry about)
	b) egcc/egcs generates very efficient asm code.

Linus uses asm in the main task scheduler so that it is absolutely clear
that the CPU will "fall through" quickly 99% of the time rather than allow
gcc take a wild guess.

David Campbell