From mboxrd@z Thu Jan 1 00:00:00 1970 From: Abramo Bagnara Subject: Re: another control API issue Date: Wed, 08 May 2002 16:00:41 +0200 Sender: alsa-devel-admin@lists.sourceforge.net Message-ID: <3CD92F89.4D5711B9@alsa-project.org> References: <200205081306.g48D6VD04392@post2.fast.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: Received: from smtp1.libero.it (smtp1.libero.it [193.70.192.51]) by alsa.alsa-project.org (8.9.3/8.9.3/SuSE Linux 8.9.3-0.1) with ESMTP id QAA07460 for ; Wed, 8 May 2002 16:01:00 +0200 Errors-To: alsa-devel-admin@lists.sourceforge.net List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: To: Paul Davis Cc: alsa-devel@alsa-project.org, Jaroslav Kysela List-Id: alsa-devel@alsa-project.org Paul Davis wrote: > > >I expected something similar. Don't you think that to have a FLOAT type > >is a better choice (more card independent, more accessible, more > >representative, etc.). > > Well, that was my initial thought. Then I remembered that we can't > have floating point code in the kernel, and its therefore unsafe to > even use this data type (an interrupt in kernel mode doesn't result in > an FP register restore, and we may have run another task in the > meantime that used the FP registers before we get back to our code). > > In this particular case, even if it was safe to store the value in a > float, the actual float value has to be computed with FP math, which > is definitely not available in the kernel. so it wouldn't help much > here. > > Sound right? Not fully. You can use FPU in kernel space with some attention (disable preemption and save/restore FPU state for critical area). -- Abramo Bagnara mailto:abramo@alsa-project.org Opera Unica Phone: +39.546.656023 Via Emilia Interna, 140 48014 Castel Bolognese (RA) - Italy ALSA project http://www.alsa-project.org It sounds good! _______________________________________________________________ Have big pipes? SourceForge.net is looking for download mirrors. We supply the hardware. You get the recognition. Email Us: bandwidth@sourceforge.net