Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932277AbdGUON2 (ORCPT ); Fri, 21 Jul 2017 10:13:28 -0400 Received: from mx2.rt-rk.com ([89.216.37.149]:50197 "EHLO mail.rt-rk.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932220AbdGUONZ (ORCPT ); Fri, 21 Jul 2017 10:13:25 -0400 From: Aleksandar Markovic To: linux-mips@linux-mips.org Cc: Aleksandar Markovic , Miodrag Dinic , Goran Ferenc , Douglas Leung , James Hogan , linux-kernel@vger.kernel.org, Paul Burton , Petar Jovanovic , Raghu Gandham , Ralf Baechle Subject: [PATCH v3 13/16] MIPS: math-emu: .: Fix some cases of zero inputs Date: Fri, 21 Jul 2017 16:09:11 +0200 Message-Id: <1500646206-2436-14-git-send-email-aleksandar.markovic@rt-rk.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1500646206-2436-1-git-send-email-aleksandar.markovic@rt-rk.com> References: <1500646206-2436-1-git-send-email-aleksandar.markovic@rt-rk.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2247 Lines: 60 From: Aleksandar Markovic Fix the cases of . when any of two multiplicands is +0 or -0, and the third input is also +0 or -0. Depending on the signs of inputs, certain special cases must be handled. The relevant example: MADDF.S fd,fs,ft: If fs contains +0.0, ft contains -0.0, and fd contains 0.0, fd is going to contain +0.0 (without this patch, it used to contain -0.0). Signed-off-by: Miodrag Dinic Signed-off-by: Goran Ferenc Signed-off-by: Aleksandar Markovic --- arch/mips/math-emu/dp_maddf.c | 8 ++++++++ arch/mips/math-emu/sp_maddf.c | 8 ++++++++ 2 files changed, 16 insertions(+) diff --git a/arch/mips/math-emu/dp_maddf.c b/arch/mips/math-emu/dp_maddf.c index 45f815d..b8b2c17 100644 --- a/arch/mips/math-emu/dp_maddf.c +++ b/arch/mips/math-emu/dp_maddf.c @@ -113,6 +113,14 @@ static union ieee754dp _dp_maddf(union ieee754dp z, union ieee754dp x, case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO): if (zc == IEEE754_CLASS_INF) return ieee754dp_inf(zs); + /* Handle cases +0 + (-0) and similar ones. */ + if (zc == IEEE754_CLASS_ZERO) { + if ((!(flags & maddf_negate_product) && (zs == (xs ^ ys))) || + ((flags & maddf_negate_product) && (zs != (xs ^ ys)))) + return z; + else + return ieee754dp_zero(ieee754_csr.rm == FPU_CSR_RD); + } /* Multiplication is 0 so just return z */ return z; diff --git a/arch/mips/math-emu/sp_maddf.c b/arch/mips/math-emu/sp_maddf.c index 76856d7..cb8597b 100644 --- a/arch/mips/math-emu/sp_maddf.c +++ b/arch/mips/math-emu/sp_maddf.c @@ -114,6 +114,14 @@ static union ieee754sp _sp_maddf(union ieee754sp z, union ieee754sp x, case CLPAIR(IEEE754_CLASS_DNORM, IEEE754_CLASS_ZERO): if (zc == IEEE754_CLASS_INF) return ieee754sp_inf(zs); + /* Handle cases +0 + (-0) and similar ones. */ + if (zc == IEEE754_CLASS_ZERO) { + if ((!(flags & maddf_negate_product) && (zs == (xs ^ ys))) || + ((flags & maddf_negate_product) && (zs != (xs ^ ys)))) + return z; + else + return ieee754sp_zero(ieee754_csr.rm == FPU_CSR_RD); + } /* Multiplication is 0 so just return z */ return z; -- 2.7.4