Accuracy of Free42 and DM42

[Thomas Okken]

The way angles around 45° are handled is necessary to make its behavior symmetrical and continuous, in the Decimal and Binary versions.

Regarding errors in the final digit: if memory serves, IEEE-754 allows transcendental functions to be off by 1 ULP, while everything else is supposed to be correct within the limits of representation, i.e. 0.5 ULP.

When I mentioned, years ago, that Free42 Decimal doesn't evaluate transcendentals to maximum precision, this was in reference to Hugh Steers' BCD20 library. (He did modify that library eventually to provide full precision for all functions, which I integrated into Free42 1.4.52.) This doesn't apply to Free42 1.5 and later.