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xen-devel
Re: [Xen-devel] code question?
On 11 Aug 2005, at 18:03, M.A. Williamson wrote:
I think that:
!!a & !b === (a != 0 ) && ( b == 0 )
It's just more efficient to do it directly using bitwise ops than to
use the full logical operators (can gcc really not optimise this sort
of thing???).
It can't optimise out short-circuit semantics. Without predicates on
instructions (like e.g. ARM has) it has to emit conditional branches.
-- Keir
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