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: AS3215 2.6.0.0/16 X-Spam-Status: No, score=-4.2 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI,SPF_HELO_PASS,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from sourceware.org (server2.sourceware.org [IPv6:2620:52:3:1:0:246e:9693:128c]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id D1A2C1F8C6 for ; Thu, 1 Jul 2021 22:28:36 +0000 (UTC) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id F10863972416 for ; Thu, 1 Jul 2021 22:28:35 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org F10863972416 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1625178516; bh=Nd2Phnpw81IulBMMmtsuwpYcfN/fXSErL83ujEknycc=; h=References:In-Reply-To:Date:Subject:To:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=G+lLlzukN+AsU96aEPfIFwiHIB54LNMykbLuH4rRVSnzfFNorvRrlxeCZYCObkzaq IVbVURiD+bOv2CIjFiDMlr+XjTL/sDTrhfq17cqroQfpWJC3cxnGkyuEgvApz33w30 sX/NWsIkcKCRXFuOFGOzisbrEd5uuWEK07WWcyfo= Received: from mail-pl1-x635.google.com (mail-pl1-x635.google.com [IPv6:2607:f8b0:4864:20::635]) by sourceware.org (Postfix) with ESMTPS id DFAF53836035 for ; Thu, 1 Jul 2021 22:28:13 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org DFAF53836035 Received: by mail-pl1-x635.google.com with SMTP id o4so1461279plg.1 for ; Thu, 01 Jul 2021 15:28:13 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Nd2Phnpw81IulBMMmtsuwpYcfN/fXSErL83ujEknycc=; b=KSQFhNTjeI9ovMAanAOjxNLsBQ8HT4TF/1LLlM8FwGCStW+izglisSKwzlsAAkfFyQ 3y3126YP+zqaC54rQ60iEPe+CZRZukSiiM2B9VrbD2ojz9VHtzxzfT+6FyZW95+TgmH7 jFT04aTdGD6rJM9KBy5nipjZaRYD9EPIeN5XGHFS73+ka+3HHHw+zVu8J/PksY9xlBu0 3cEPS94Hasur8yKH//3B/V490IUTKXxma/asB/2Rh5HMcTNxKHzjytUaH02K2HTNFET3 RO91AUSFqm67Rlaf4BejAYARR4eKLu6aXWJSAT6go7bIs2UZSnPQX45B1jcagMWHaQNe H4xA== X-Gm-Message-State: AOAM532Io/RZoDHINgNERfq1PGMGbFiAh2gU9hG5EzbXT82Z5A/Lm1rR W6Y6QrF7P8AXEnQG01cKa5fK3+UkhNhRo8RXQS0= X-Google-Smtp-Source: ABdhPJxejmGNO4hPphsKrwkIsUHAPffbBLT+phAtsgxwjlnqBnkRNkS7dvtp0HdjD9SGJydoAIyVDw+YPUkREcyO4PA= X-Received: by 2002:a17:902:aa4a:b029:10e:f98c:2b83 with SMTP id c10-20020a170902aa4ab029010ef98c2b83mr1786838plr.62.1625178493017; Thu, 01 Jul 2021 15:28:13 -0700 (PDT) MIME-Version: 1.0 References: <20210701210537.51272-1-hjl.tools@gmail.com> In-Reply-To: Date: Thu, 1 Jul 2021 15:27:37 -0700 Message-ID: Subject: Re: [PATCH] Add optional _Float16 support To: Joseph Myers Content-Type: text/plain; charset="UTF-8" X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: "H.J. Lu via Libc-alpha" Reply-To: "H.J. Lu" Cc: llvm-dev@lists.llvm.org, GCC Patches , GNU C Library , IA32 System V Application Binary Interface Errors-To: libc-alpha-bounces+e=80x24.org@sourceware.org Sender: "Libc-alpha" On Thu, Jul 1, 2021 at 3:10 PM Joseph Myers wrote: > > On Thu, 1 Jul 2021, H.J. Lu via Gcc-patches wrote: > > > 2. Return _Float16 and _Complex _Float16 values in %xmm0/%xmm1 registers. > > That restricts use of _Float16 to processors with SSE. Is that what we > want in the ABI, or should _Float16 be available with base 32-bit x86 > architecture features only, much like _Float128 and the decimal FP types Yes, _Float16 requires XMM registers. > are? (If it is restricted to SSE, we can of course ensure relevant libgcc > functions are built with SSE enabled, and likewise in glibc if that gains > _Float16 functions, though maybe with some extra complications to get > relevant testcases to run whenever possible.) > _Float16 functions in libgcc should be compiled with SSE enabled. BTW, _Float16 software emulation may require more than just SSE since we need to do _Float16 load and store with XMM registers. There is no 16bit load/store for XMM registers without AVX512FP16. -- H.J.