WP31s error recovery

[Sanjeev Visvanatha]

(03-04-2015 12:56 AM)Bit Wrote:  I'm not sure what exactly you mean by original 31S release level. The problem is not related to my other patches, it's present in the official versions. It's been present for a long time but I don't know when it was introduced, you'd need to bisect the code to figure it out, which is not something I have the time for right now.

I had some time to dig around. It looks like the issue was introduced at the time of the UNDO implementation at r3551. I loaded a commit before that (r3532) that I had committed before the UNDO implementation, and the Back Arrow (<-) behaviour for the 1st example is identical to the WP 34S.

I believe it was Pauli that implemented UNDO at r3551. It is not unreasonable that an unexpected 'feature' was introduced.