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

[Paul Dale]

(02-04-2014 03:14 AM)Bit Wrote:  I've created a patch to improve the Y register display in the WP 34S. Really good Y register display is impossible on the measly screen of the HP 30b but even a less than perfect implementation can improve usability.

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.

Quote:The original code directly manipulated the horizontal position (the 'x' variable) in set_status_sized() in order to align the number displayed. This seemed like an ad-hoc solution that wouldn't scale to support new features with different alignment requirements so I came up with something else. The '\007' character (the gradian symbol) starts an escape sequence that specifies the width of the next character explicitly and whether the big or the small font should be used.

Yeah, I didn't like this much at the time but it squeezed a fraction more out of the pixel section of the display and it wasn't going into the real 34S firmware release ever so we let it pass. I'm not sure I entirely like specifying the character width using an escape code either. All the display driving on the 34S is character based and this was done intentionally. Well, it was before Marcus implemented the printer support and the registers holding graphical data were allow to be displayed.

One point which I felt was important for the 34S dot matrix display is that nothing ever bounces around. e.g. the gradian indicator always stays in exactly the same position regardless of what is before it. Likewise for all the other annunicators, not even a single pixel of motion. To me, this looks more professional and streamlined -- it makes the firmware look finished. The y-register display code broke this, specifically with the aforementioned x position modification.


Still, it looks like you are making great progress understanding and modifying the 34S firmware. I am glad for this.


- Pauli