From 9cb4e398c2f95c1e837fe9c570e124a55259f725 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Alex=20Benn=C3=A9e?= Date: Mon, 16 Apr 2018 14:54:42 +0100 Subject: fpu/softfloat: check for Inf / x or 0 / x before /0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The re-factoring of div_floats changed the order of checking meaning an operation like -inf/0 erroneously raises the divbyzero flag. IEEE-754 (2008) specifies this should only occur for operations on finite operands. We fix this by moving the check on the dividend being Inf/0 to before the divisor is zero check. Signed-off-by: Alex Bennée Message-id: 20180416135442.30606-1-alex.bennee@linaro.org Cc: Bastian Koppelmann Reviewed-by: Bastian Koppelmann Tested-by: Bastian Koppelmann Signed-off-by: Peter Maydell --- fpu/softfloat.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'fpu') diff --git a/fpu/softfloat.c b/fpu/softfloat.c index fb8663f59e..d90d79d777 100644 --- a/fpu/softfloat.c +++ b/fpu/softfloat.c @@ -1146,6 +1146,11 @@ static FloatParts div_floats(FloatParts a, FloatParts b, float_status *s) a.cls = float_class_dnan; return a; } + /* Inf / x or 0 / x */ + if (a.cls == float_class_inf || a.cls == float_class_zero) { + a.sign = sign; + return a; + } /* Div 0 => Inf */ if (b.cls == float_class_zero) { s->float_exception_flags |= float_flag_divbyzero; @@ -1153,11 +1158,6 @@ static FloatParts div_floats(FloatParts a, FloatParts b, float_status *s) a.sign = sign; return a; } - /* Inf / x or 0 / x */ - if (a.cls == float_class_inf || a.cls == float_class_zero) { - a.sign = sign; - return a; - } /* Div by Inf */ if (b.cls == float_class_inf) { a.cls = float_class_zero; -- cgit v1.2.1