[WP 34S] Enhanced Y register display: fractions, bugfixes etc.

[Bit]

(02-04-2014 05:56 AM)Paul Dale Wrote:  When the Y register display was implemented, I vaguely remember working out the absolute worst case and it was zero or one significant digits of the mantissa being visible -- double precision, negative number with large negative exponent or some such.

The worst case I could reproduce was three significant digits for double precision numbers like -2.345e-2345. Fewer significant digits appear only if rounding makes it necessary, e.g. for 1.99999e200, but that's unavoidable. This was already handled well by the original Y register code (aside from cutting off the last digit occasionally). Maybe you remember an older state of affairs? If not, I'd really like to know how to trigger the worst case scenario you mentioned. If it still happens, I'm quite sure it can be fixed.

(02-04-2014 05:56 AM)Paul Dale Wrote:  I'm not sure I entirely like specifying the character width using an escape code either.

I couldn't think of another way to do it without significantly increasing the size of the firmware. The gradian symbol was chosen because it's only used for a single purpose in a single place and, as far as I could tell, it isn't part of any catalog, so it's easy to make sure an escape sequence is never created unintentionally. The gradian symbol can still be displayed, it just has to be part of an escape sequence. All of the escape magic is within #ifdef's or code branches that are guaranteed to be optimized away if unused. None of it is compiled in unless some feature selected needs it.

(02-04-2014 05:56 AM)Paul Dale Wrote:  One point which I felt was important for the 34S dot matrix display is that nothing ever bounces around.

I completely agree and I believe the new Y register display code achieves the same. If it doesn't, it's a bug I intend to fix.