Date: Mon, 16 Feb 2004 13:51:25 +0000 From: Colin Percival <colin.percival@wadham.ox.ac.uk> To: Trent Nelson <trent@teleri.net> Cc: freebsd-hackers@freebsd.org Subject: Re: Branch prediction Message-ID: <6.0.1.1.1.20040216134828.0390bfa0@imap.sfu.ca> In-Reply-To: <20040215164231.GA54709@teleri.net> References: <20040215164231.GA54709@teleri.net>
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At 16:42 15/02/2004, Trent Nelson wrote: >does the old adage of "always predict >false" still hold true the first time a branch is encountered? Most processors predict that forward branches are not taken, and backward branches are taken (since backward branches occur most often in loops). Of course, some processors now have hints (conditional-jump- which-is-usually-taken, conditional-jump-which-is-usually-not- taken, etc.) Colin Percival
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