41C sunrise/sunset program listing: what are these strange "dot" steps?

[Dave Britten]

I was looking at this sunrise/sunset program, and quite a few of the steps are just a mysterious dot character: •

https://www.hpmuseum.org/cgi-sys/cgiwrap...?read=1131

It doesn't look like a decimal point used elsewhere in the listing, but is that all it is? And if so, what's the significance of using a lone decimal point instead of 0?

[rprosperi]

(05-23-2020 01:01 AM)Dave Britten Wrote:  It doesn't look like a decimal point used elsewhere in the listing, but is that all it is? And if so, what's the significance of using a lone decimal point instead of 0?

It executes faster then entering 0. Although this is not synthetic (you just type [.]) it is similar to using E instead of 1 (this is synthetic). They both simply execute faster in a program.

[Thomas Okken]

Looking at the DOY routine, the dot in line 8 has to be a minus in order for the code to make sense. However, line 11 should be FS? 31, not FS? 01. And how would a minus get turned into a dot while there are normal minuses elsewhere in these listings? I don't think I'd trust this code...

[Thomas Okken]

It looks like a bug in whatever tool was originally used to transfer or convert the HP-41C programs. All minus commands were turned into 0x95 (Windows-1252 bullet), while all other minuses were left alone (numbers, strings, HMS- commands). Maybe they were supposed to be rendered as 0x96 (en dash).

[Dave Britten]

(05-23-2020 10:59 AM)Thomas Okken Wrote:  It looks like a bug in whatever tool was originally used to transfer or convert the HP-41C programs. All minus commands were turned into 0x95 (Windows-1252 bullet), while all other minuses were left alone (numbers, strings, HMS- commands). Maybe they were supposed to be rendered as 0x96 (en dash).

I was starting to wonder if it was some kind of text-encoding mishap. I tried all the supported encodings in Firefox, and none of them seem to change the bullet to a minus, so I can't imagine what happened there.

The 33S/35S programs on that page look fishy too. There are a bunch of occurrences of "1." that look like they're supposed to be a subtraction operation.

[cruff]

For the SUN program, line 32 should also be "FS? 00".

After all of the corrections that have been mentioned, it runs correctly.

Does anyone know of the corrections to be applied based on altitude above mean sea level?