| Message ID | 20171211125705.16120-7-alex.bennee@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | re-factor softfloat and add fp16 functions | expand |
On 12/11/2017 04:56 AM, Alex Bennée wrote: > While a comparison between a QNaN and a number will return the number > it is not the same with a signaling NaN. In this case the SNaN will > "win" and after potentially raising an exception it will be quietened. > > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > > --- > v2 > - added return for propageFloat > --- > fpu/softfloat.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) I suppose this fixes minmax for float128 too, and is thus not redundant with patch 18? Reviewed-by: Richard Henderson <richard.henderson@linaro.org> r~
Richard Henderson <richard.henderson@linaro.org> writes: > On 12/11/2017 04:56 AM, Alex Bennée wrote: >> While a comparison between a QNaN and a number will return the number >> it is not the same with a signaling NaN. In this case the SNaN will >> "win" and after potentially raising an exception it will be quietened. >> >> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> >> >> --- >> v2 >> - added return for propageFloat >> --- >> fpu/softfloat.c | 8 ++++++-- >> 1 file changed, 6 insertions(+), 2 deletions(-) > > I suppose this fixes minmax for float128 too, > and is thus not redundant with patch 18? It was never expanded so I guess no one does float128 minmax's at the moment. > > Reviewed-by: Richard Henderson <richard.henderson@linaro.org> > > > r~ -- Alex Bennée
diff --git a/fpu/softfloat.c b/fpu/softfloat.c index 3a4ab1355f..44c043924e 100644 --- a/fpu/softfloat.c +++ b/fpu/softfloat.c @@ -7683,6 +7683,7 @@ int float128_compare_quiet(float128 a, float128 b, float_status *status) * minnum() and maxnum() functions. These are similar to the min() * and max() functions but if one of the arguments is a QNaN and * the other is numerical then the numerical argument is returned. + * SNaNs will get quietened before being returned. * minnum() and maxnum correspond to the IEEE 754-2008 minNum() * and maxNum() operations. min() and max() are the typical min/max * semantics provided by many CPUs which predate that specification. @@ -7703,11 +7704,14 @@ static inline float ## s float ## s ## _minmax(float ## s a, float ## s b, \ if (float ## s ## _is_any_nan(a) || \ float ## s ## _is_any_nan(b)) { \ if (isieee) { \ - if (float ## s ## _is_quiet_nan(a, status) && \ + if (float ## s ## _is_signaling_nan(a, status) || \ + float ## s ## _is_signaling_nan(b, status)) { \ + return propagateFloat ## s ## NaN(a, b, status); \ + } else if (float ## s ## _is_quiet_nan(a, status) && \ !float ## s ##_is_any_nan(b)) { \ return b; \ } else if (float ## s ## _is_quiet_nan(b, status) && \ - !float ## s ## _is_any_nan(a)) { \ + !float ## s ## _is_any_nan(a)) { \ return a; \ } \ } \
While a comparison between a QNaN and a number will return the number it is not the same with a signaling NaN. In this case the SNaN will "win" and after potentially raising an exception it will be quietened. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> --- v2 - added return for propageFloat --- fpu/softfloat.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) -- 2.15.1