Free42 with IEEE 754-2008 decimal floating-point -- interested in a sneak preview?

[Thomas Okken]

Yes, that's definitely the angle reduction code at work -- it changes the sign of the result depending on which quadrant the angle was in before the reduction.
I'll fix that, but now I wonder how many other situations there are like this? The Intel library and the angle reduction code aren't the only new features in 1.5; this is also the first that relies on library functions to display numbers (sprintf() for binary, bid128_to_string() for decimal, both followed by code that massages the output to make it look like it should on an HP-42S), and those functions make a point of rendering signed zero, while the old Free42-specific number formatting code didn't. There may have been signed zeroes haunting the hallways in Free42 Binary since version 1.0... You just couldn't see them. (Not in Free42 Decimal, since BCD20 doesn't support signed zero, if I remember correctly.)
To make it behave normally, preventing the number display code from rendering signed zero may be the right thing to do. -0 behaves exactly like +0, except for what happens when you divide by it, and Free42 doesn't allow division by zero anyway.