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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-45ef34c50f6sm31552175f8f.16.2026.06.01.14.45.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 01 Jun 2026 14:45:34 -0700 (PDT) Date: Mon, 1 Jun 2026 22:45:33 +0100 From: David Laight To: "H. Peter Anvin" Cc: "Maciej W. Rozycki" , Christian Ludloff , Dave Hansen , Richard Weinberger , Sohil Mehta , "Ahmed S. Darwish" , Borislav Petkov , x86@kernel.org, Thomas Gleixner , Ingo Molnar , Josh Poimboeuf , Andrew Cooper , Tony Luck , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/3] x86/cpu/intel: Simplify F00F bug notice using pr_notice_once() Message-ID: <20260601224533.6dc1b37b@pumpkin> In-Reply-To: <6C32834F-6EC5-4A36-A6A6-132C2D52E45A@zytor.com> References: <20260526162041.5b7e6614@pumpkin> <48C91A0E-043C-4E24-99E5-DE64B9F47C3A@zytor.com> <20260527100943.37d67776@pumpkin> <710E29BB-58E1-4071-A841-483CCE8D141D@zytor.com> <6C32834F-6EC5-4A36-A6A6-132C2D52E45A@zytor.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Mon, 01 Jun 2026 07:43:32 -0700 "H. Peter Anvin" wrote: > On May 27, 2026 9:14:10 AM PDT, "Maciej W. Rozycki" wrote: > >On Wed, 27 May 2026, H. Peter Anvin wrote: > > > >> >> If full precision is enabled there are a whole lot of horrid corner cases. > >> >> Mostly due to correctly generating the FP signals when the 80bit return > >> >> value from a function is written to a 64bit 'double'. > >> > > >> > No IEEE quad for `long double' still, not even on 64-bit hw? Weird. > >> > >> The ABI was designed in 2003 or so... > > > > Hmm, usually it's hardware that gets features first with software to > >follow. For instance by now the POWER port has gained three `long double' > >formats in their psABI, all of which can coexist in a single system (I got > >that covered in the course of the glibc test improvement effort too). > > > > Maciej > > The x87 psABI does have a __float128 type IIRC. > Isn't that the 16bit exponent, 64bit mantissa of the x87 fpu? It has to aligned so there are 48bits unused. -- David