From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.3 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FORGED_GMAIL_RCVD, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_PASS,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id 7A5F71F453 for ; Mon, 21 Jan 2019 23:25:54 +0000 (UTC) DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-type; q=dns; s=default; b=jVMV Of6OPnlinm2977qx13fOO2LNI5nd6uj+11L8dVrVCbptw1nkfY0d2ysRuxe/nYNt SKWLDq0Jc8wSy+yNIyHo5FmwwafawRjffJ5DVz/ynEWOBkmR+W9Kda7IyvPTiXVr RkcLabgxx7Sx5ks9lHzP+WwOuQhEjwHSLEmtmqU= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-type; s=default; bh=ajR02a4wfe ixEyjHbbMPh43f/VM=; b=pwhrVB8hcZ7dUzekcXMk9jWY3P94q7RMjzBN0msqm6 Re1tbc66CRXe6W2x747XlYYvOWwTaUDFCQ4ZqA0pqqBhlXIFb5kqRBHSy5G/uL8/ Y29eXQ7kYYBxQYP3HsFX7DWDcbGbrTIwQvbugXB0XukBvg55Eu5A+F3EfTpqZSq8 Q= Received: (qmail 13511 invoked by alias); 21 Jan 2019 23:25:51 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 13387 invoked by uid 89); 21 Jan 2019 23:25:39 -0000 Authentication-Results: sourceware.org; auth=none X-HELO: mail-oi1-f193.google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=7Bv3/bjpMPjgNSDYgTK5uLxnxIBe+Ssi16EFXMvZBIw=; b=DMHDS4M3akFmuZq+2gnhZpzhpelSSJCXgt+2cuJ4hZR9IlU8AKNS7UKqVeacuvFjbK lqMGqT9v8rNdxTT3znSo+H767iowQLN3jjWjqJNxYWCMH4uQWqvW01b3ZYCxizneU4Ar /1h/29+uruvKfcDHhoxdCVJfpHR7cZbLu/GwbMojzV9LFGvaZwGKLO96TlVxkbceRcRn cVJn3jw/5hQNGWH1NHa0OEX6hcHfzW5/Nk5H6txgf0r8nkWqGhCz+s/xoOeqv1U3/vkd UbDWKs5IjG7+VSch/DCRJqYQBkYrNCE0MYVQY/I59GMg96aLZIIuAHXjIowi8HVU9zw9 tmyg== MIME-Version: 1.0 References: <20190121194255.13036-1-hjl.tools@gmail.com> In-Reply-To: From: "H.J. Lu" Date: Mon, 21 Jan 2019 15:24:59 -0800 Message-ID: Subject: Re: [PATCH] soft-fp: Add floattixf.c and floatuntixf.c To: Joseph Myers Cc: GNU C Library Content-Type: text/plain; charset="UTF-8" On Mon, Jan 21, 2019 at 2:39 PM Joseph Myers wrote: > > On Mon, 21 Jan 2019, H.J. Lu wrote: > > > TI->XF conversions in libgcc2.c: > > > > XFtype > > __floatdixf (DWtype u) > > { > > XFtype d = (Wtype) (u >> W_TYPE_SIZE); > > d *= Wtype_MAXp1_F; > > d += (UWtype)u; > > return d; > > } > > > > have no rounding mode support. Add floattixf.c and floatuntixf.c to > > That doesn't need rounding mode support. XFmode has 64-bit precision, so > all 64-bit integer values can be represented exactly in XFmode, so that > function only has a single possibly inexact operation (the addition), so > only a single rounding, which will use the hardware rounding mode. (The > x87 rounding mode, not the SSE rounding mode, of course, but nothing > should make those two rounding modes different other than a limited amount > of code inside glibc that optimizes by knowing that certain code only ever > uses one of the floating-point units so only needs that rounding mode > changed.) > > > soft-fp to support rounding mode. > > I see no reasonable use for XFmode soft-fp functions in libgcc (other than > the conversions to/from TFmode, of course); XFmode is only used in libgcc > when it's a hardware type, which means the libgcc2.c functions that are > based around hardware operations are preferable. > You are right. I withdrew this patch. Thanks. -- H.J.