From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <199911261206.NAA23788@denx.local.net> To: Michael Schmitz cc: linuxppc-dev@lists.linuxppc.org, linuxppc-embedded@lists.linuxppc.org From: Wolfgang Denk Subject: Re: bootloader & head.S weirdness & restructuring Mime-version: 1.0 Content-type: text/plain; charset=ISO-8859-1 In-reply-to: Your message of "Fri, 26 Nov 1999 10:42:03 +0100." Date: Fri, 26 Nov 1999 13:06:21 +0100 Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: In message Michael Schmitz wrote: > > > > #if defined(CONFIG_x) || defined(CONFIG_y) || defined(CONFIG_z) > > > > ... > > > > #endif ... > Plus it has the added benefit that you can still build kernels that > support a range of hardware (by making has_feature_a not const 0 or 1 but > something like feature_present(a) :-) If you don't need this, both are > equivalent though. This depends if the compiler has a chance to decide which code is needed and which not. Otherwise it cannot optimize away dead code. > Worried about wasting a few cycles on the branch? I've never noticed a No, it's the code size that matters on many embedded systems. The target is a minimal kernel code size. And improved performance is a most welcome add-on. Wolfgang Denk -- Software Engineering: Embedded and Realtime Systems, Embedded Linux Phone: (+49)-8142-4596-87 Fax: (+49)-8142-4596-88 Email: wd@denx.de "...one of the main causes of the fall of the Roman Empire was that, lacking zero, they had no way to indicate successful termination of their C programs." - Robert Firth ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/