New -21 and -25 apps for iPhone

Maciej Bartosiak has ported my simulation code for the -21 and -25 calculators to iOS, so they may be used on the iPhone, iPod Touch, and iPad. The apps are RPN-21 and RPN-25. I hope no one objects to my posting this announcement; I thought some of the regulars here might be interested in these apps.


Really nice looking calculator! Well, at least the 21 version. I'm not paying $2.99 for a iPhone version, sorry. ;-)



You can credit Maciej for the visual appearance, as that's entirely his doing. I'll take the blame for any bugs in the simulation.


I got them both for my iPad. Finally an HP-25 emulator!!! I am a happy camper!!!




Glad you like it! If we're successful with it, more models will likely follow.



An HP 27 and/or HP 29c would be nice. ;-)


Thanks! these are great apps :-)


Nice looking for sure. BTW, please note all shifted functions are located below of the primary operations :-)

For edition 1.1 I'd suggest an improved exponent format - e.g. sin^-1 looks a bit primitive spelled this way IMHO. And a capital Pi is used ... :-/


From your lips to the developers' ears!!

I hope Eric is reading this!



Edited: 6 Mar 2011, 9:25 a.m.


I don't mind paying a reasonable fees for these emulators.


Great app !
A couple of comments:

1/This is obviously not a HP-25C: killing the app resets memory; on Iphone 4 this is not much of a problem, you can use multitasking to keep the memory state, but still - is there any plan to upgrade it to a HP-25C in future ?

2/I think there is a bug: I never owned a HP-25 but I think it is supposed to display the next instruction to be excuted if "SST" is held down (and then, to excute the instruction). Here, nothing of this kind. Is this a bug or an intended behaviour ?

Would be awsome to have the 34C (and of course, the 65 and 67, if ever their card reader behaviour is reversed-engineered...).




Great work! Unfortunately, my original iPod Touch is stuck at OS 3.1.3 so I'll have to wait until I upgrade to a newer "i" device.




You're right about SST on the 25. I'll talk to Maciej about that and continuous memory.



I have downloaded the 25 on my iPad. The calculator looks nice. A help file would have helped. However it is nice to play with an HP calculator in 1970s style.


Hi Eric,
Thanks, the new version is on the Appstore and corrects the 'SST' bug ! It does not implement continuous memory, though.
Could you maybe tell us what is scheduled for Nonpareil for Iphone ? Especially:
-If the calculators that are already in Nonpareil, especially the 34C and 33C, could be soon on the Appstore ? would be great !
-If the calculators that are not yet in Nonpareil, but that you have been mentionning in 2008 as almost-ready (especially, the 67 and the 29C) could come soon as well ?
-and if other calcls (especially the 65, would be great) could come and when ?

Would love of these beauties on my Iphone :)

Thanks and cheers,


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