From owner-freebsd-hackers@freebsd.org Sat May 25 22:54:07 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 0D47F15B89E2 for ; Sat, 25 May 2019 22:54:07 +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 EB45A8DD7D for ; Sat, 25 May 2019 22:54:05 +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 x4PMrwwn056509 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Sat, 25 May 2019 15:53:58 -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 x4PMrv0v056508; Sat, 25 May 2019 15:53:57 -0700 (PDT) (envelope-from sgk) Date: Sat, 25 May 2019 15:53:57 -0700 From: Steve Kargl To: Yuri Cc: Konstantin Belousov , Freebsd hackers list Subject: Re: What is the portable 128-bit floating point type? Message-ID: <20190525225357.GA56490@troutmask.apl.washington.edu> Reply-To: sgk@troutmask.apl.washington.edu References: <20190525200437.GV2748@kib.kiev.ua> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.2 (2019-01-07) X-Rspamd-Queue-Id: EB45A8DD7D X-Spamd-Bar: / Authentication-Results: mx1.freebsd.org X-Spamd-Result: default: False [0.23 / 15.00]; HAS_REPLYTO(0.00)[sgk@troutmask.apl.washington.edu]; REPLYTO_ADDR_EQ_FROM(0.00)[]; RCVD_COUNT_THREE(0.00)[3]; TO_DN_ALL(0.00)[]; RCVD_IN_DNSWL_MED(-0.20)[21.76.95.128.list.dnswl.org : 127.0.11.2]; MX_GOOD(-0.01)[troutmask.apl.washington.edu]; NEURAL_HAM_SHORT(-0.60)[-0.599,0]; FROM_EQ_ENVFROM(0.00)[]; RCVD_TLS_LAST(0.00)[]; R_DKIM_NA(0.00)[]; ASN(0.00)[asn:73, ipnet:128.95.0.0/16, country:US]; SUBJECT_ENDS_QUESTION(1.00)[]; MID_RHS_MATCH_FROM(0.00)[]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-0.86)[-0.857,0]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[3]; MIME_GOOD(-0.10)[text/plain]; MIME_TRACE(0.00)[0:+]; DMARC_NA(0.00)[washington.edu]; AUTH_NA(1.00)[]; TO_MATCH_ENVRCPT_SOME(0.00)[]; NEURAL_SPAM_LONG(0.01)[0.007,0]; IP_SCORE(-0.01)[ip: (0.08), ipnet: 128.95.0.0/16(0.07), asn: 73(-0.14), country: US(-0.06)]; R_SPF_NA(0.00)[]; FREEMAIL_CC(0.00)[gmail.com] 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 22:54:07 -0000 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? > gcc version 5 or 6 and up comes with libquadmath. It is a software implementation of IEEE 128-bit floating point math. You need sparc64 to have a 128-bit hardware support. -- Steve