From owner-freebsd-hackers@freebsd.org Sat May 25 23:13:13 2019 Return-Path: Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 6547715B91A1 for ; Sat, 25 May 2019 23:13:13 +0000 (UTC) (envelope-from sgk@troutmask.apl.washington.edu) Received: from troutmask.apl.washington.edu (troutmask.apl.washington.edu [128.95.76.21]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "troutmask", Issuer "troutmask" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id BBB448EADE for ; Sat, 25 May 2019 23:13:12 +0000 (UTC) (envelope-from sgk@troutmask.apl.washington.edu) Received: from troutmask.apl.washington.edu (localhost [127.0.0.1]) by troutmask.apl.washington.edu (8.15.2/8.15.2) with ESMTPS id x4PNDAKH056599 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Sat, 25 May 2019 16:13:10 -0700 (PDT) (envelope-from sgk@troutmask.apl.washington.edu) Received: (from sgk@localhost) by troutmask.apl.washington.edu (8.15.2/8.15.2/Submit) id x4PNDAmY056598; Sat, 25 May 2019 16:13:10 -0700 (PDT) (envelope-from sgk) Date: Sat, 25 May 2019 16:13:10 -0700 From: Steve Kargl To: Konstantin Belousov Cc: Yuri , Freebsd hackers list Subject: Re: What is the portable 128-bit floating point type? Message-ID: <20190525231310.GB56490@troutmask.apl.washington.edu> Reply-To: sgk@troutmask.apl.washington.edu References: <20190525200437.GV2748@kib.kiev.ua> <20190525210311.GW2748@kib.kiev.ua> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190525210311.GW2748@kib.kiev.ua> User-Agent: Mutt/1.11.2 (2019-01-07) X-Rspamd-Queue-Id: BBB448EADE X-Spamd-Bar: ------ Authentication-Results: mx1.freebsd.org X-Spamd-Result: default: False [-6.99 / 15.00]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; REPLY(-4.00)[]; NEURAL_HAM_SHORT(-0.99)[-0.986,0] X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 25 May 2019 23:13:13 -0000 On Sun, May 26, 2019 at 12:03:11AM +0300, Konstantin Belousov wrote: > On Sat, May 25, 2019 at 01:50:24PM -0700, Yuri wrote: > > On 2019-05-25 13:04, Konstantin Belousov wrote: > > > Neither i386 nor amd64 have hardware-supported 128 bit floating point > > > type. long double is defined by both i386 and amd64 Unix ABI as 80 bits > > > (10 bytes) representation as defined by IEEEE FP standard and supported > > > by x87 FPU (not-SSE). The difference in size is due to the different > > > natural alignment between 32 and 64 bit ISA. > > > > > > So it looks like there is no true quad-precision float available. > > > > > > Based on this conversation https://github.com/bluescarni/mppp/issues/186 > > FreeBSD used to support __float128. Why was it removed? > No idea, it seems to be clang-specific. gcc 8.3 does accept the type. > On the other hand, I have no idea if any support is required from > libgcc (probably it is), and we almost certainly do not have it in > the base library. This is part of the problem with gfortran finding the wrong libgcc_s.so. -- Steve