Buggy Hewlett Packard 15C Scientific Calculator iPhone App?

[Gerson W. Barbosa]

The HP-15C app by Hewlett-Packard returns blinking results after program executions (version 2.0.1, iPhone 4s and iOS 7 here).
This is not much of a concern, however. I would just press CHS (or x<>y) twice to stop it from blinking. The main issue for me is the default American number format which makes the app totally useless for me. Please correct me if I am wrong, but apparently there is no way to change it to European number format (DECIMAL POINT IS COMMA). May we expect more updates? Thanks!

[Gerson W. Barbosa]

The decimal separator can be changed to comma under Settings (iOS). Likewise the noisy key clicks some have complained about can be disabled. The blinking display still persists. At least no PSE bug here (unlike my real hp 15c LE).

[Marcio]

Gerson,

I know this thread is rather old but.. would you mind checking if the iPhone app also has this bug?

Thanks

[Gerson W. Barbosa]

Márcio,

Exactly the same bug on the iPhone version. No problem (regarding this) on the real HP-15C LE.
No update since then. It seems HP just doesn't care.

[Thomas Klemm]

(11-27-2015 09:56 AM)Marcio Wrote:  I no longer trust the 15C app by HP to run my programs

Do they have at least successfully replicated the CHS and Stack Lift bug of the original HP-15C?

Cheers
Thomas

[Marcio]

(11-27-2015 10:39 AM)Thomas Klemm Wrote:  

(11-27-2015 09:56 AM)Marcio Wrote:  I no longer trust the 15C app by HP to run my programs

Do they have at least successfully replicated the CHS and Stack Lift bug of the original HP-15C?

Cheers
Thomas

Oh my! Another 15C bug. The third one!

And yes, the Android emulator has this bug too.

[Marcio]

Thomas,

I didn't see these bugs (of the original 15C) on the 15C LE bug list. Did they get kicked out of the new firmware?

Thanks

[Thomas Klemm]

(11-27-2015 11:29 AM)Marcio Wrote:  Did they get kicked out of the new firmware?

I doubt they changed the original ROM in their emulator. Thus this bug is probably present in the real HP-15C LE as well. But I think this list contains only bugs of the emulator and not of the ROM.

HTH
Thomas

[Marcio]

Well, if the LE still has the bugs of the original, I think the list should be updated so users know what troubles to avoid, especially this one related to the CHS command.

I can't understand why well-known and discussed-to-death old bugs are not eliminated and new ones are introduced.

[Katie Wasserman]

(11-27-2015 01:00 PM)Thomas Klemm Wrote:  I doubt they changed the original ROM in their emulator. Thus this bug is probably present in the real HP-15C LE as well. But I think this list contains only bugs of the emulator and not of the ROM.

That's correct. I only noted bugs introduced in the 15C LE not bugs that were carried over from the original.

[Gerson W. Barbosa]

(11-27-2015 10:39 AM)Thomas Klemm Wrote:  

(11-27-2015 09:56 AM)Marcio Wrote:  I no longer trust the 15C app by HP to run my programs

Do they have at least successfully replicated the CHS and Stack Lift bug of the original HP-15C?

Cheers
Thomas

Yes, both the emulator and the HP-15C LE. No problem about this, though. What bugs me (no pun intended) is the HP-15C LE and the emulator known bugs not having been addressed thus far. HP of yore is no more (See Hewlett-Packard Integrity and "The Bug").

Best regards,

Gerson.

[Thomas Klemm]

(11-27-2015 01:19 PM)Marcio Wrote:  Well, if the LE still has the bugs of the original, I think the list should be updated so users know what troubles to avoid, especially this one related to the CHS command.

Not sure if there's a list of known HP-15C bugs.

Quote:I can't understand why well-known and discussed-to-death old bugs are not eliminated

Fixing a bug in a ROM is difficult. As far as I know even HP doesn't have the original source files anymore. Thus all you can do is disassemble the ROM to get assembler code. But without comments this tends to be difficult to understand. Just as an illustration here's a method of the HP-48 written in SysRPL (not assembler) that I once tried to understand. Without the comment in the header I wouldn't have had an idea what's going on.
The assembly code often uses tricks that are not apparent. So even if you understand what's going on you still don't understand why it's needed. I once fixed a bug in the ROM of the HP-80. The fix was trivial: I just had to switch a bit. But it took me a long time to find it.
And then even if you find the reason for the bug it's often not that easy to fix it because the fix has to fit in the limited amount of bytes you have in the ROM.

"Life is short and ROM is full."
-- Bill Wickes

In addition to that you want to be sure that you don't introduce another bug with your fix. For this you usually have a suite of tests. But we currently don't have anything like that.

Quote:and new ones are introduced.

The specification for these emulators was probably the existing Nonpareil written in C. Though it's not too difficult to translate that to Java (for Android) or Objective C (for iOS) the part dealing with the GUI had probably to be written from scratch. This explains why most of the bugs are somehow GUI related. I assume that handling the PSE-function had to be rewritten as well. Otherwise the pause would only take a few milliseconds instead of about 1 second if the emulator runs at full speed.

This forum is probably not the correct place to file a bug report. I suggest to try at HP or send a message to Tim or Cyrille.

Cheers
Thomas

[Marcio]

(11-27-2015 03:03 PM)Thomas Klemm Wrote:  Not sure if there's a list of known HP-15C bugs.

What I meant to say was that I would have added those 3 of the original to the 15C LE bug list because they are present. Or at least point to the 3 threads in which the bugs were discussed. This is of course my opinion only.

Thomas, thank you for the detailed explanation!

Marcio

[Oulan]

Hi,

I am interested on a list of the original HP15C bugs.
I already dis-assembled and partially commented the rom of the 15 to patch it to have more memory (as swissmicro did to have more memory too).
I still not have released it in go15c as there are some mis-behavior for matrix larger than 9x9 (and it is not really that useful, use go42s if more power is needed).

Perhaps some original bugs could be corrected ?

P.S. PSE behavior is correctly done if you write a correct emulator

[Marcio]

I have never seen or heard of such a list, but if you are interested, I can point to these:

Bug 1 (2007)
Bug 2 (2011)
Bug 3 (2012)

[Thomas Klemm]

(11-27-2015 03:37 PM)Oulan Wrote:  I already dis-assembled and partially commented the rom of the 15

Would you make that public? Since a lot of operations are similar to the HP-41C it's VASM listing could be used as a basis for comments and names of labels. However the complex- and matrix-operations will probably be the tough part to analyse.

Cheers
Thomas

[Oulan]

I think that the copyright problem of the rom is also valid for a dis-assembled listing no ?