On Fri, 1 May 2020, Alex Bennée wrote: > > Joseph Myers <jos...@codesourcery.com> writes: > > > The softfloat function addFloatx80Sigs, used for addition of values > > with the same sign and subtraction of values with opposite sign, fails > > to handle the case where the two values both have biased exponent zero > > and there is a carry resulting from adding the significands, which can > > occur if one or both values are pseudo-denormals (biased exponent > > zero, explicit integer bit 1). Add a check for that case, so making > > the results match those seen on x86 hardware for pseudo-denormals. > > Hmm running the super detailed test: > > fp-test -s -l 2 -r all extF80_add extF80_sub > > I don't see any difference between before and after the patch. This > makes me wonder if we are (or rather TestFloat) is missing something in > it's test case.
It could well only be testing kinds of floating-point representations that are meaningful in IEEE interchange formats. Pseudo-denormals don't exist in IEEE interchange formats (and nor do pseudo-NaNs, pseudo-infinities and un-normals, which are dealt with in floatx80_invalid_encoding). -- Joseph S. Myers jos...@codesourcery.com