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[114.34.229.221]) by smtp.gmail.com with ESMTPSA id o15sm577529pjk.48.2021.04.19.18.31.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Apr 2021 18:31:52 -0700 (PDT) From: frank.chang@sifive.com To: qemu-devel@nongnu.org, qemu-riscv@nongnu.org Subject: [PATCH v2] fpu/softfloat: set invalid excp flag for RISC-V muladd instructions Date: Tue, 20 Apr 2021 09:31:48 +0800 Message-Id: <20210420013150.21992-1-frank.chang@sifive.com> X-Mailer: git-send-email 2.17.1 Received-SPF: pass client-ip=2607:f8b0:4864:20::436; envelope-from=frank.chang@sifive.com; helo=mail-pf1-x436.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=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Frank Chang , Peter Maydell , =?utf-8?q?Alex_Benn=C3=A9e?= , Aurelien Jarno Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Frank Chang In IEEE 754-2008 spec: Invalid operation exception is signaled when doing: fusedMultiplyAdd(0, Inf, c) or fusedMultiplyAdd(Inf, 0, c) unless c is a quiet NaN; if c is a quiet NaN then it is implementation defined whether the invalid operation exception is signaled. In RISC-V Unprivileged ISA spec: The fused multiply-add instructions must set the invalid operation exception flag when the multiplicands are Inf and zero, even when the addend is a quiet NaN. This commit set invalid operation execption flag for RISC-V when multiplicands of muladd instructions are Inf and zero. Signed-off-by: Frank Chang Reviewed-by: Richard Henderson --- fpu/softfloat-specialize.c.inc | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fpu/softfloat-specialize.c.inc b/fpu/softfloat-specialize.c.inc index c2f87addb25..12f29fbfc5e 100644 --- a/fpu/softfloat-specialize.c.inc +++ b/fpu/softfloat-specialize.c.inc @@ -624,6 +624,12 @@ static int pickNaNMulAdd(FloatClass a_cls, FloatClass b_cls, FloatClass c_cls, } else { return 1; } +#elif defined(TARGET_RISCV) + /* For RISC-V, InvalidOp is set when multiplicands are Inf and zero */ + if (infzero) { + float_raise(float_flag_invalid, status); + } + return 3; /* deafult NaN */ #elif defined(TARGET_XTENSA) /* * For Xtensa, the (inf,zero,nan) case sets InvalidOp and returns