From nobody Mon Feb 9 03:14:46 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=reject dis=none) header.from=sifive.com ARC-Seal: i=1; a=rsa-sha256; t=1770182410; cv=none; d=zohomail.com; s=zohoarc; b=koUc8bxdgJbaCj0pGCKm9DnXznhb8GpsgahpkB01z6NdXdB2XLsJTersgkoGsuLz2xephqe0Ie0tcCfSji6CKkOE6gyfgDZhh+j6ju1wHRnrxJlTPj2kPBCFpIxp/mbtInt5ynmsMzfuDAhdAEDsMa3a43H/7yyfCOdJQRCkzLA= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1770182410; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=I/dvFpuAgHW9LatoJl8ikUFTHhk3Jg3flnJ8ORHZmgw=; b=WEaeuj5dZhGnMOUuW52EC7UQf4GfO0yU9T0tKpRdeLRiMJuhhKscx0VaIrZ/QdyxunHHIqky+LrD5SIGF/VIq0yl0CjMLaAuIiQnOELW1pq8+3YShUTHoT+cf4kS9+7sonbIrk8JbgJ9u8Zj5pSEqp/xoF3hAP1i7gpww2OSV+c= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=reject dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1770182410638898.2974062203426; Tue, 3 Feb 2026 21:20:10 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vnVHP-0007Ql-Qb; Wed, 04 Feb 2026 00:18:19 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vnVHO-0007QO-8Z for qemu-devel@nongnu.org; Wed, 04 Feb 2026 00:18:18 -0500 Received: from mail-pj1-x1029.google.com ([2607:f8b0:4864:20::1029]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1vnVHM-0007y3-O3 for qemu-devel@nongnu.org; Wed, 04 Feb 2026 00:18:18 -0500 Received: by mail-pj1-x1029.google.com with SMTP id 98e67ed59e1d1-34c708702dfso3488690a91.1 for ; Tue, 03 Feb 2026 21:18:16 -0800 (PST) Received: from duncan.localdomain (114-35-142-126.hinet-ip.hinet.net. [114.35.142.126]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-35485eb8d90sm1266314a91.12.2026.02.03.21.18.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Feb 2026 21:18:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sifive.com; s=google; t=1770182295; x=1770787095; darn=nongnu.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=I/dvFpuAgHW9LatoJl8ikUFTHhk3Jg3flnJ8ORHZmgw=; b=nI5TUchl+Xz6G84pwp+iZN+rYx0hnxRnCZbdloVBZkQZEwhBajcXtjhS2G+p/2kunH G/okrm+3jrqbc5MblxUT6fX0Bkkgdff9jUCrqV2dcaYOQoEv7NaCA0ljv7bXSURXLMpX jc7eVejs5yGTL7f4qohD+9Rl3iaR0SNq+4Ni8L7YlDAjYIdzraZ9Vd7dkQrtL401TUGC TWhGQ7QJ+1oTx+mwIVNo1z+YhW/eK2XlXQivJlEXRUUUNuH1+e61jdOS59XbVHHhXSkE AviiXz+ClNovFA+x+ueVsy4/a19gDeI0J/vfn9wPCVwOngdOBz0E80nC2FKnT2xr5oKA NmCA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1770182295; x=1770787095; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=I/dvFpuAgHW9LatoJl8ikUFTHhk3Jg3flnJ8ORHZmgw=; b=XLScBIXp96KIPOVGiUdKsgQF6XpQnJF8BEm8X4JwzMBvTphz4B7xYD2aJibKxgvkia XbDFyOH1bdwUQNJR6/ZYSdG6apQrb7IWSoqldtPkCin9uUbpZLh5Bp92rEAYAN6fQvdo 8kHAlIthcVJDS7POWGRlX3/bQWuD+nquGj92P4NPuzro0emED38iFLMdLwky4ZnWXcKd BsQUE+g0qpFxhAcRAWoGxcxi4/WzvqTo8YoT1gaNFxABeqBnf7Jcc/hixrzaJVtjO+vx cQ6Ey05cS28L5b/YS+851tPrhkNpGZ3UqIAa0GGE3HPrEmYP6m9mOSIxio2lRT5HSjf4 5t4w== X-Gm-Message-State: AOJu0Ywe0xCVAJg1JmsBAUctmIfF6uu5k7Gjqyagi9mYMtbp2PlmS3Lh R9Ot967uYOZG+Ns9ula2bpjgw4XTlJIrAtSuXdxzeINVSAfdNwL81Xd9mlM845chJRWCbWjBLZC 2XthJx9f1AjtYSyd5mpoBN/puZut4PIyBOyf09Zb3YgjcU2qSSA1U99WtOzQX6CaKeHTicGakHn EyGoDgvaFxS+DogrEaaxhX7NVVTgmfZddZyOMaO0gqlb2b X-Gm-Gg: AZuq6aJYH5m3agDTtkbbBL7hyJCfReZoRXD2Qwa98JEt9nlA0b8qLZA8rpSPiYvgDRU WSD+V/XNQHWDWvM/IsG5eXtcV9iJdP8u9juemV/3T2Q7dQ2cudrwNTto/ZE62AfKpOujmxkFX5A 8wb6YTXoI9NTpypiTLTxAsfqZemVN5bYToeQqSoS6ixCgjLiYQU5XgUuRtRmYOf5RIKvaI7aLij ELkpQx3zc/O1CE+jrr+BW4pKGA+Fth8gH+z3f3X47cAa9Dk4nGKIcN9Vwx7302sxN/Ggkc0X8IJ Q+ZTwBjY84OkJ8UzNKEJOoWsaMlGKyzw/qpbpzigOKsT3azcnqGYW2B+lzGmzVqsO0HQCfuCjlJ tM9g++OPOA1UmWt/FnqUMS5QWaGIqcAYAMAdXwmYGVreCQ1xAHbEdht7a+qnYnGyUNh2XtMszrp OCiXG0e79sSWrXBD7o87zy5QdJAJqaDZ+oMskVSi1mYLzCxn8/MKYmcnsC7jvpbxw0Ul5ohiUjf KXKwvM8+296NGIUSXiEsoShbQ== X-Received: by 2002:a17:90b:57c5:b0:353:38c8:b612 with SMTP id 98e67ed59e1d1-354870db3d6mr1547969a91.12.1770182295083; Tue, 03 Feb 2026 21:18:15 -0800 (PST) From: Max Chou To: qemu-devel@nongnu.org, qemu-riscv@nongnu.org Cc: Palmer Dabbelt , Alistair Francis , Aurelien Jarno , Peter Maydell , =?UTF-8?q?Alex=20Benn=C3=A9e?= , Paolo Bonzini , Richard Henderson , Eduardo Habkost , Weiwei Li , Daniel Henrique Barboza , Liu Zhiwei , Max Chou Subject: [PATCH v3 04/19] target/i386: Fix pseudo-NaN handling in FPATAN/FYL2XP1/FYL2X helpers Date: Wed, 4 Feb 2026 13:17:40 +0800 Message-ID: <20260204051756.667397-5-max.chou@sifive.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260204051756.667397-1-max.chou@sifive.com> References: <20260204051756.667397-1-max.chou@sifive.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2607:f8b0:4864:20::1029; envelope-from=max.chou@sifive.com; helo=mail-pj1-x1029.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @sifive.com) X-ZM-MESSAGEID: 1770182412643154100 Content-Type: text/plain; charset="utf-8" According to Intel's x87 FPU specification (Table 8-10, Vol. 1), arithmetic operations on operands in unsupported formats (including pseudo-NaNs) must return the QNaN floating-point indefinite value. The helper functions for FPATAN, FYL2XP1, and FYL2X incorrectly check for signaling NaN before checking for invalid encodings. This causes pseudo-NaNs to be treated as valid signaling NaNs and silenced, rather than being rejected as unsupported formats. Reorder the checks to test floatx80_invalid_encoding before floatx80_is_signaling_nan, matching the correct behavior already implemented in helper_fscale. Signed-off-by: Max Chou Reviewed-by: Richard Henderson --- target/i386/tcg/fpu_helper.c | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) diff --git a/target/i386/tcg/fpu_helper.c b/target/i386/tcg/fpu_helper.c index b3b23823fd..37c83ded38 100644 --- a/target/i386/tcg/fpu_helper.c +++ b/target/i386/tcg/fpu_helper.c @@ -1377,16 +1377,16 @@ void helper_fpatan(CPUX86State *env) int32_t arg1_exp =3D extractFloatx80Exp(ST1); bool arg1_sign =3D extractFloatx80Sign(ST1); =20 - if (floatx80_is_signaling_nan(ST0, &env->fp_status)) { + if (floatx80_invalid_encoding(ST0, &env->fp_status) || + floatx80_invalid_encoding(ST1, &env->fp_status)) { + float_raise(float_flag_invalid, &env->fp_status); + ST1 =3D floatx80_default_nan(&env->fp_status); + } else if (floatx80_is_signaling_nan(ST0, &env->fp_status)) { float_raise(float_flag_invalid, &env->fp_status); ST1 =3D floatx80_silence_nan(ST0, &env->fp_status); } else if (floatx80_is_signaling_nan(ST1, &env->fp_status)) { float_raise(float_flag_invalid, &env->fp_status); ST1 =3D floatx80_silence_nan(ST1, &env->fp_status); - } else if (floatx80_invalid_encoding(ST0, &env->fp_status) || - floatx80_invalid_encoding(ST1, &env->fp_status)) { - float_raise(float_flag_invalid, &env->fp_status); - ST1 =3D floatx80_default_nan(&env->fp_status); } else if (floatx80_is_any_nan(ST0)) { ST1 =3D ST0; } else if (floatx80_is_any_nan(ST1)) { @@ -2061,16 +2061,16 @@ void helper_fyl2xp1(CPUX86State *env) int32_t arg1_exp =3D extractFloatx80Exp(ST1); bool arg1_sign =3D extractFloatx80Sign(ST1); =20 - if (floatx80_is_signaling_nan(ST0, &env->fp_status)) { + if (floatx80_invalid_encoding(ST0, &env->fp_status) || + floatx80_invalid_encoding(ST1, &env->fp_status)) { + float_raise(float_flag_invalid, &env->fp_status); + ST1 =3D floatx80_default_nan(&env->fp_status); + } else if (floatx80_is_signaling_nan(ST0, &env->fp_status)) { float_raise(float_flag_invalid, &env->fp_status); ST1 =3D floatx80_silence_nan(ST0, &env->fp_status); } else if (floatx80_is_signaling_nan(ST1, &env->fp_status)) { float_raise(float_flag_invalid, &env->fp_status); ST1 =3D floatx80_silence_nan(ST1, &env->fp_status); - } else if (floatx80_invalid_encoding(ST0, &env->fp_status) || - floatx80_invalid_encoding(ST1, &env->fp_status)) { - float_raise(float_flag_invalid, &env->fp_status); - ST1 =3D floatx80_default_nan(&env->fp_status); } else if (floatx80_is_any_nan(ST0)) { ST1 =3D ST0; } else if (floatx80_is_any_nan(ST1)) { @@ -2159,16 +2159,16 @@ void helper_fyl2x(CPUX86State *env) int32_t arg1_exp =3D extractFloatx80Exp(ST1); bool arg1_sign =3D extractFloatx80Sign(ST1); =20 - if (floatx80_is_signaling_nan(ST0, &env->fp_status)) { + if (floatx80_invalid_encoding(ST0, &env->fp_status) || + floatx80_invalid_encoding(ST1, &env->fp_status)) { + float_raise(float_flag_invalid, &env->fp_status); + ST1 =3D floatx80_default_nan(&env->fp_status); + } else if (floatx80_is_signaling_nan(ST0, &env->fp_status)) { float_raise(float_flag_invalid, &env->fp_status); ST1 =3D floatx80_silence_nan(ST0, &env->fp_status); } else if (floatx80_is_signaling_nan(ST1, &env->fp_status)) { float_raise(float_flag_invalid, &env->fp_status); ST1 =3D floatx80_silence_nan(ST1, &env->fp_status); - } else if (floatx80_invalid_encoding(ST0, &env->fp_status) || - floatx80_invalid_encoding(ST1, &env->fp_status)) { - float_raise(float_flag_invalid, &env->fp_status); - ST1 =3D floatx80_default_nan(&env->fp_status); } else if (floatx80_is_any_nan(ST0)) { ST1 =3D ST0; } else if (floatx80_is_any_nan(ST1)) { --=20 2.52.0