Date: Thu, 30 Sep 1999 00:37:38 +0900 From: KATO Takenori <kato@ganko.eps.nagoya-u.ac.jp> To: bde@zeta.org.au Cc: nyan@FreeBSD.org, imp@village.org, winter@jurai.net, kato@FreeBSD.org, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org, FreeBSD98-hackers@jp.freebsd.org Subject: Re: cvs commit: src/sys/conf files src/sys/i386/conf files.i386 Message-ID: <19990930003738A.kato@gneiss.eps.nagoya-u.ac.jp> In-Reply-To: Your message of "Wed, 29 Sep 1999 03:06:50 %2B1000 (EST)" <Pine.BSF.4.10.9909290231150.7599-100000@alphplex.bde.org> References: <Pine.BSF.4.10.9909290231150.7599-100000@alphplex.bde.org>
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Bruce Evans <bde@zeta.org.au> wrote: > Doesn't this require changing all drivers that currently use the > bus space functions to be changed to initialise their sc->sc_bsh.base > instead of their sc->sc_bsh? This is uglier than casting. It would be hard work. But compilng LINT kernel may tell us missing changes. > 1) Only one bus type supported, and the tag for that is a compile-time > constant. Otherwise, there will be an extra branch in the bus space > routines for getting to the inirect case. This branch will cost > more than indirection on most machines. Of cource, your method has advantage to performance. But if we use your method (using bus_space_foo with zero offset) in a driver, I think that there isn't much meaing of usinge bus space. If performance loss is not negligible, separating such code into MD part and using inb/outb may solve the problem. If performance loss is negligible, using bus_space_foo with non-zero offset could not have performacne problem. -----------------------------------------------+--------------------------+ KATO Takenori <kato@ganko.eps.nagoya-u.ac.jp> | FreeBSD | Dept. Earth Planet. Sci, Nagoya Univ. | The power to serve! | Nagoya, 464-8602, Japan | http://www.FreeBSD.org/ | ++++ FreeBSD(98) 3.2: Rev. 01 available! |http://www.jp.FreeBSD.org/| ++++ FreeBSD(98) 2.2.8: Rev. 02 available! +==========================+ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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