From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 30791 invoked by alias); 5 Jun 2015 06:44:48 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Received: (qmail 30781 invoked by uid 89); 5 Jun 2015 06:44:47 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.8 required=5.0 tests=AWL,BAYES_00,KAM_LAZY_DOMAIN_SECURITY,SPF_HELO_PASS,T_RP_MATCHES_RCVD autolearn=no version=3.3.2 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Fri, 05 Jun 2015 06:44:46 +0000 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (Postfix) with ESMTPS id 27D982DC411; Fri, 5 Jun 2015 06:44:44 +0000 (UTC) Received: from greed.delorie.com (ovpn-113-25.phx2.redhat.com [10.3.113.25]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t556ihW3021774 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Fri, 5 Jun 2015 02:44:43 -0400 Received: from greed.delorie.com (greed.delorie.com [127.0.0.1]) by greed.delorie.com (8.14.4/8.14.4) with ESMTP id t556igMu027745; Fri, 5 Jun 2015 02:44:42 -0400 Received: (from dj@localhost) by greed.delorie.com (8.14.4/8.14.4/Submit) id t556igDi027743; Fri, 5 Jun 2015 02:44:42 -0400 Date: Fri, 05 Jun 2015 08:02:00 -0000 Message-Id: <201506050644.t556igDi027743@greed.delorie.com> From: DJ Delorie To: Kaushik Phatak CC: gcc-patches@gcc.gnu.org, nickc@redhat.com In-reply-to: (message from Kaushik Phatak on Fri, 5 Jun 2015 06:37:36 +0000) Subject: Re: [PATCH : RL78] Disable interrupts during hardware multiplication routines References: X-IsSubscribed: yes X-SW-Source: 2015-06/txt/msg00448.txt.bz2 Have you compared the latency of the multiply instructions to the overhead of saving those registers in the interrupt handler? What about the case where performance is priority, and the developer knows that the interrupt handlers don't use the multiply registers? Also, your code doesn't properly handle the case where the interrupts are already disabled when those functions are called. It would re-enable interrupts before the main code was prepared for it.