From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/11176 Path: news.gmane.org!.POSTED!not-for-mail From: David Edelsohn Newsgroups: gmane.linux.lib.musl.general Subject: Re: [PATCH] aarch64: add single instruction math functions Date: Tue, 21 Mar 2017 12:50:46 -0400 Message-ID: References: <20170319042644.GP2082@port70.net> <20170319150522.GT1693@brightrain.aerifal.cx> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Trace: blaine.gmane.org 1490115062 13411 195.159.176.226 (21 Mar 2017 16:51:02 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 21 Mar 2017 16:51:02 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-11192-gllmg-musl=m.gmane.org@lists.openwall.com Tue Mar 21 17:50:57 2017 Return-path: Envelope-to: gllmg-musl@m.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by blaine.gmane.org with smtp (Exim 4.84_2) (envelope-from ) id 1cqMzm-0002h7-Jd for gllmg-musl@m.gmane.org; Tue, 21 Mar 2017 17:50:54 +0100 Original-Received: (qmail 7547 invoked by uid 550); 21 Mar 2017 16:50:59 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Original-Received: (qmail 7523 invoked from network); 21 Mar 2017 16:50:58 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=Bw7wECQaxy/k3dbmQGZV7aiATsPH+PMFPUVwfRv94kM=; b=mQ5kPbLpOtAsrc25v+EInOzzqmw9CGw9BAYVZK+xc0ILgNJmN0lT8XARg2Gz/GInU3 I6SeGZKVPg4CRVvqzhNC+pRTb/WVCCQuwYAd38Ra+Zuv7cL7302ZWxmfSXZkaK4fcL1E zPZeI+lxRTSJyWgBXFrhyayD5p0HKGUwc/LDjQ84rC8TKEMPBoWjvj/DXtWnlE0nJBTP C2oZFuACbGSDK4jQqiwc2XtlWpoSnTXTmGcvefqLXuRKiz9A063VVLA/7Q4VFXjpdQE0 /QbJmjmsUQfR6KOtmTlMQWmJq3UiCiggrDEch/T5Q1HiMgLQMQo3Ad4SVAd84/HGJM6K Ryvg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to; bh=Bw7wECQaxy/k3dbmQGZV7aiATsPH+PMFPUVwfRv94kM=; b=C6TpSWoC2qobmAuQPAfZQ7FAX6fRWLvmXWVrMkCF0hMZkHerw786ER0VKiNqSmZRj7 sIPW4SaeVTT+IzKNA6ZOnxZD0AkcNDvHFuL0qD9x7oe0QdEnMJt8lGk1VQWluQfPD2qU HooatKR4I0QeSIn26+qEyuSO8zdl6Txvuj1Tv6F+Vm7wvDC7C9tFZu1b6UtMQkiN/4lf ga0LX0Lzc0Od+2t1dwpxriprO6sZCBXHT5GKgTbC6mjPIuiM6m1Z15h0axbCL/Gh1Vhe fXjpYAzjP1soskO5XGkcw7O2tM0KU8aBmOKkJku1U+ZDb1ON56rq9GGN6dzesX8QYnR/ lgLg== X-Gm-Message-State: AFeK/H0i9Q27/PKF1o0CvbjU7KrbATphh9LQAhneyr/OJkm3y774VqjWpHx0IxJu+ssFaKvRgYv0F5OGuu7WNA== X-Received: by 10.55.104.21 with SMTP id d21mr30565158qkc.49.1490115046664; Tue, 21 Mar 2017 09:50:46 -0700 (PDT) In-Reply-To: <20170319150522.GT1693@brightrain.aerifal.cx> Xref: news.gmane.org gmane.linux.lib.musl.general:11176 Archived-At: On Sun, Mar 19, 2017 at 11:05 AM, Rich Felker wrote: > On Sun, Mar 19, 2017 at 08:55:58AM -0400, David Edelsohn wrote: >> I thought that the goal of musl was "Minimal machine-specific code". > > My interpretation of minimal is two-fold: > > - minimal amount of arch-specific coding required to bring up a new > arch. > > - when arch-specific code is present by necessity or for optimization > (speed or size), keeping complexity, maintenance cost, and room for > arch-specific bugs minimal. > > This is not intended to preclude use of single-instruction primitives > (see existing code for x86, etc.) for math functions or even critical > things that may be somewhat more complex like memcpy. This policy makes maintenance more difficult and bugs more difficult to analyze because different ports of musl libc may use less common code. Single instruction primitives occur more often in CISC architectures by definition, so this preferences CISC. This policy makes the decision process for architecture-specific changes much more arbitrary. - David