From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Joel Soete" Subject: Re: [parisc-linux] [gcc] should we teach gcc some new tricks? Date: Thu, 23 Jun 2005 08:10:19 +0200 Message-ID: <4282FEEE0000FA5F@mail-6-bnl.tiscali.it> References: <20050623052753.GA20584@colo.lackof.org> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-15" Cc: parisc-linux@lists.parisc-linux.org To: "Grant Grundler" Return-Path: In-Reply-To: <20050623052753.GA20584@colo.lackof.org> List-Id: parisc-linux developers list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: parisc-linux-bounces@lists.parisc-linux.org > -- Original Message -- > Date: Wed, 22 Jun 2005 23:27:53 -0600 > From: Grant Grundler > To: Joel Soete > Cc: parisc-linux@lists.parisc-linux.org > Subject: Re: [parisc-linux] [gcc] should we teach gcc some new tricks? > > > On Wed, Jun 22, 2005 at 07:54:54PM +0000, Joel Soete wrote: > > of fp registers? > > or how may I try to define it as accurately as possible? > > (I objdump a operating 2.6.12-rc.-pa. 64bit to grep some 'fr[12][0..9= ]' > and > > all of them seems to be used? > > Of course they will all be used - kernel has to save and restore > process state when switching context. Oops I missed it (my bad) > You have to look at each > use and determine why FP is being used. There shouldn't > be that many different uses. > Thanks for enlightenment, I still have to make a lot of progress ;-) > > Do I have to look elsewhere; tausq also spoke about: sic > > [...]One proposal that has been talked about before is if we can > > compile a version of the millicode lib that uses limited fpregs range= > > and compile the kernel using this new option that Dave is talking abo= ut, > > then we will be able to get by using a (much) smaller subset of fp re= gs > > and we won't have to save/restore them in the kernel. ) > > That's correct - but we will still have to save/restore all FP regs > on a general context switch - just a subset of those when > entering/leaving the kernel (e.g. handling an external interrupt). > Thanks, Joel _______________________________________________ parisc-linux mailing list parisc-linux@lists.parisc-linux.org http://lists.parisc-linux.org/mailman/listinfo/parisc-linux