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| author | Alex Bennée <alex.bennee@linaro.org> | 2018-04-16 14:54:42 +0100 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2018-04-16 18:40:48 +0100 |
| commit | 9cb4e398c2f95c1e837fe9c570e124a55259f725 (patch) | |
| tree | 774ac24416cac3cfa0933ac7594094d68598ae56 | |
| parent | 2a6b5372d7bad038fe27f9c60e85ef5c8a15e311 (diff) | |
| download | qemu-9cb4e398c2f95c1e837fe9c570e124a55259f725.zip qemu-9cb4e398c2f95c1e837fe9c570e124a55259f725.tar.gz qemu-9cb4e398c2f95c1e837fe9c570e124a55259f725.tar.bz2 | |
fpu/softfloat: check for Inf / x or 0 / x before /0
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 <alex.bennee@linaro.org>
Message-id: 20180416135442.30606-1-alex.bennee@linaro.org
Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Reviewed-by: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Tested-by: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
| -rw-r--r-- | fpu/softfloat.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/fpu/softfloat.c b/fpu/softfloat.c index fb8663f..d90d79d 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; |