Le 28/04/2020 à 20:43, Alex Bennée a écrit : > > KONRAD Frederic <frederic.kon...@adacore.com> writes: > >> The MC68881 say about infinities (3.2.4): >> >> "*For the extended precision format, the most significant bit of the >> mantissa (the integer bit) is a don't care." >> >> https://www.nxp.com/docs/en/reference-manual/MC68881UM.pdf >> >> The m68k extended format is implemented with the floatx80 and >> floatx80_invalid_encoding currently treats 0x7fff00000000000000000000 as >> an invalid encoding. This patch fixes floatx80_invalid_encoding so it >> accepts that the most significant bit of the mantissa can be 0. >> >> This bug can be revealed with the following code which pushes extended >> infinity on the stack as a double and then reloads it as a double. It >> should normally be converted and read back as infinity and is currently >> read back as nan: > > Do you have any real HW on which you could record some .ref files for > the various multiarch float tests we have (float_convs/float_madds)? > Does this different of invalid encoding show up when you add them?
On my side, in the past when I started to implement m68k FPU, I used TestFloat and SoftFloat I have ported to m68k and I compare the result in QEMU and in a Quadra 800. https://github.com/vivier/m68k-testfloat https://github.com/vivier/m68k-softfloat I also used the gcc and libc testsuite to detect problems but this was a very slow process... I have also ported RISU to m68k, but I didn't add FPU test in it (does it support FPU test?). Thanks, Laurent
