From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Mosberger Date: Wed, 28 Jun 2000 00:20:27 +0000 Subject: Re: [Linux-ia64] Using f6-f11 floating-point registers Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: linux-ia64@vger.kernel.org >>>>> On Tue, 27 Jun 2000 18:02:09 -0400, Jun Nakajima said: Jun> At this point, the kernel is using more than f6-f11 Jun> floating-point registers (using -mfixed-range=F10-f15,f32-f127, Jun> i.e. those are *not* available to the kernel, but the others, Jun> like f16-f31 are). If the compiler or someone writing assembly code thinks it's beneficial to use a preserved fp register, we should let them use it. Of course, they'll have to explicitly save/restore the register before using it, but there may well be cases where this is beneficial, so we shouldn't prevent it for no good reason. Jun> When do we support the reduced FP model (EL_IA_64_REDUCEFP), Jun> where only f6-f11 are used by the kernel? For the record, I have no plans to adopt the REDUCEFP model. I want to reserve the right for kernel developers to tweak the kernel register usage without having to talk to a standards body. Sorry. --david