42S "reserved" flags

[Dave Britten]

According to the 42S manual, there are a number of "reserved" flags, with no actual description given. Does anybody know what, if anything, these flags do or indicate? I haven't been able to find any info after a bit of Google searching.

14
17-18
31-33
54
64
67
78-80

[grsbanks]

A lot of these are a hang-over from the HP-41C.

I do know that flag 31 was used by the time module (both the 82182A module for 41C/CV and the built-in module in the 41CX) to keep track of DMY/MDY format and this has been carried forward into both the SwissMicros DM41 and into Free42 (and, by extension, the DM42).

[Dave Britten]

Ah, that makes perfect sense; I hadn't thought to look at the 41C(X) flag list. Naturally they'd want to reserve a few flags that different modules could use. I'll have to check some manuals to see if those had any function in a stock 41.

Basically, I'm hoping to find some undocumented behavior that would indicate a user selected a MENU item with the Shift key.

[Gene]

Some are explained here... From the Free 42 manual for the 42s: http://thomasokken.com/free42/42s.pdf

Code:


00–10 and 81–99: These 30 flags are not related to the calculators status but are just “binary
memories” you can use for what you want.
11: When you turn on the calculator if the flag 11 is set the calculator runs the program where the
“calculator's pointer” is stopped and clears the flag 11.
24: If this flag is set the calculator will ignore error messages. “Out of Range” will appear as
9.99999999999E499 in the HP-42S and as 1.7977E308 in Free42. This is important if you
want to prevent an unwanted stop during a program.
26: Turns audio on.
28: Use '.' instead of ',' (default).
29: If set the calculator separates digits in groups of three. For example: 5000000 becomes 5,000,000.
(default)
36–80: You cannot change the flags from 36 to 80.
44: Always on. If true the calculator does not turn off after about 10 minutes.
65: Matrix editor.
68–71: Base modes. CCCC=Decimal (default), CCCS=Binary, CSSS=Octal and SSSS=Hexadecimal.
It is a shame! Why not only two? :)
73: This flag if true makes the calculator to show complex numbers in polar notation.

[Thomas Okken]

(01-15-2018 04:24 PM)Dave Britten Wrote:  According to the 42S manual, there are a number of "reserved" flags, with no actual description given. Does anybody know what, if anything, these flags do or indicate? I haven't been able to find any info after a bit of Google searching.

14
17-18
31-33
54
64
67
78-80

Some of those gaps are flags that mean something on the HP-41 but not on the 42S, like flag 14, which is the write-protect override for the card reader. But of course that only applies to flags 0-55; flags 56 and up don't exist on the HP-41.

Here's a partial list from an earlier thread: http://www.hpmuseum.org/forum/post-75057.html#pid75057

[Dieter]

(01-15-2018 07:20 PM)Gene Wrote:  Some are explained here... From the Free 42 manual for the 42s: http://thomasokken.com/free42/42s.pdf

Code:

24: If this flag is set the calculator will ignore error messages. “Out of Range” will appear as 9.99999999999E499 in the HP-42S 
and as 1.7977E308 in Free42. This is important if you want to prevent an unwanted stop during a program.

Cave! As on the HP41, with flag 24 set the 42s only ignores overflows, but no other errors. This flags is still set after an overflow has occured. In this case the largest possible number is returned, i.e. 9,99999999999 E+499 on a real 42s, or 1 E+6145 on Free42 Decimal, and obviously 1,79...E+308 on Free42 Binary.

The general error-ignore-flag both on the 41 and the 42s is flag 25. If this flag is set and an error occurs this operation is ignored and the program continues. Also flag 25 is cleared so that you can check whether an error has occured or not.

Dieter

[Dieter]

(01-15-2018 05:59 PM)Dave Britten Wrote:  Basically, I'm hoping to find some undocumented behavior that would indicate a user selected a MENU item with the Shift key.

This won't help on the 42s and your particular problem, but on the HP41 series there indeed is a flag that records the Shift state: if flag 47 is set the SHIFT annunciator in the display is on and thus the Shift key has been pressed. You can actually test this flag after the Shift key has been pressed during a PSE command. ;-)

Dieter

[Gene]

More info from http://www.finseth.com/hpdata/hp42s.php

(Edited with Dieter's observations...thx)

Flags: 100, of which 0-10 and 81-99 are user and the rest system or reserved
0-4 show annunciator when set
11 auto execution
12 print double wide
13 print lower case
15-16 HPIL printer: 0)manual 1)normal 2)trace 3)trace w/stack print using the flags as a two-digit binary
21 printer enabled
22 numeric input available
23 alpha input available
24 ignore range errors
25 ignore any errors & clear
26 Clear - audio output is ignored Set - audio output is enabled
27 custom mode is active
28 radix mark: Clear is a comma, set is a period.
29 digit groupings shown: Clear - no Set - yes
30 stack lift disable
34 AGRAPH merging: 0) OR 1) duplicate "on" get turned off 2) overwrite 3) XOR
36-39 number of digits, 0-15 by using the four flags as a binary number.
40-41 display format: 0)sci 1)eng 2)fix 3)all by using the two flags as a two-digit binary
42-43 angle mode: 0)deg 1)rad 2)grad 3)rad by using the two flags as a two-digit binary
44 continuous on
45 currently solving equation
46 currently integrating
47 variable menu active
48 alpha keyboard active
49 low battery
50 set when a message is displayed line 1
51 set when a message is displayed line 2
52 program mode
53 INPUT in progress
55 printer exists
56 curve fit model: 1)linear 2)log 4)exponential 8)power
60 all \GS mode
61 logarithmic model invalid
62 exponential model invalid
63 power model invalid
65 matrix editor in use
66 auto grow matrices
68 base: 0)decimal 1)binary 7)octal 15)hexadecimal
72 local label
73 polar mode
74 real result only
75 programmable menu selected
76 matrix wrap, edge to edge
77 matrix wrap, first to last

[Dieter]

(01-15-2018 10:09 PM)Gene Wrote:  26 audio output is ignored

Flag 26 enables audio output. If flag 26 is cleared all sound is suppressed.

(01-15-2018 10:09 PM)Gene Wrote:  28 radix mark: 0). 1),

Exactly the other way round: if flag 28 is set (!) the radix mark is a dot. If cleared it's a comma.

(01-15-2018 10:09 PM)Gene Wrote:  36 number of digits, 0-15

That's flags 36, 37, 38 and 39 combined, representing a four-digit binary number.

(01-15-2018 10:09 PM)Gene Wrote:  40 display format: 0)sci 1)eng 2)fix 3)all
42 angle mode: 0)deg 1)rad 2)grad 3)rad

Same here: flag 40 & 41 or flag 42 & 43 combined represent a two-digit binary number.

Dieter

[Gene]

Hmm. Odd, since that was exactly copied from the source listed... guess that's been a typo for years! :-)

[Sylvain Cote]

HP-41 Flags Description from Jeremy Smith QRG

[Massimo Gnerucci]

(01-16-2018 01:18 AM)Sylvain Cote Wrote:  HP-41 Flags Description from Jeremy Smith QRG

Right. Since there's no "ALL" mode on the 41.
Flags 40-41 set (not directly achievable) turns on the FIX/ENG display vs FIX/SCI.

[Dave Britten]

(01-15-2018 08:46 PM)Dieter Wrote:  This won't help on the 42s and your particular problem, but on the HP41 series there indeed is a flag that records the Shift state: if flag 47 is set the SHIFT annunciator in the display is on and thus the Shift key has been pressed. You can actually test this flag after the Shift key has been pressed during a PSE command. ;-)

Dieter

Interesting. It's strange that they didn't keep some form of that around in the 42S. A lot of their financial calculators let you do Shift + "n" to store 12*X into n. I'm pretty sure that includes the 17BII, but there doesn't seem to be a way to implement that UX on a 42S.

Thanks for all the detective work, everyone.