Free42 – An HP-42S Calculator Simulator • Hacker News Board

Re: Free42 – An HP-42S Calculator Simulator

#21

Post by Thorrez » Fri, May 12, 2023, 6:08 AM UTC

nvy wrote: post #19

userbinator wrote: post #14

This IMHO very important information is buried near the bottom of the page: The HP-42S represents numbers with a 12-digit decimal mantissa, and an exponent from 10^−499 to 10^499; Free42 Decimal uses a 34-digit decimal mantissa, and an exponent from 10^−6143 to 10^6144; and Free42 Binary uses native binary floating-point, which on all currently supported platforms is IEEE-754 double precision, with a 53-bit binary ma…

The way you're using "decimal floating point" seems to imply there is a "floating point" that is not "decimal". My understanding is that "decimal", in the context of programming, is a less-precise term to mean floating-point (i.e. encompassing IEEE 754 floats, double- vs single-precision, etc), because they're all binary numbers if you dig deep enough, right? But apparently I am incorrect/underinformed about this. Wh…

Decimal means base 10. Decimus is the Latin word for 10, and deci- is the SI prefix for 1/10, e.g. decimeter is 1/10 of a meter. Decimal floating point is x*10^y whereas binary floating point is x*2^y . Compare to hexadecimal which means base 16.

Re: Free42 – An HP-42S Calculator Simulator

#22

Post by nvy » Fri, May 12, 2023, 6:39 AM UTC

Thorrez wrote: post #21

nvy wrote: post #19

Earlier quoted context omitted.

The way you're using "decimal floating point" seems to imply there is a "floating point" that is not "decimal". My understanding is that "decimal", in the context of programming, is a less-precise term to mean floating-point (i.e. encompassing IEEE 754 floats, double- vs single-precision, etc), because they're all binary numbers if you dig deep enough, right? But apparently I am incorrect/underinformed about this. Wh…

Decimal means base 10. Decimus is the Latin word for 10, and deci- is the SI prefix for 1/10, e.g. decimeter is 1/10 of a meter. Decimal floating point is x*10^y whereas binary floating point is x*2^y . Compare to hexadecimal which means base 16.

Derp. I misunderstood.

Re: Free42 – An HP-42S Calculator Simulator

#23

Post by jjav » Fri, May 12, 2023, 6:55 AM UTC

ralphc wrote: post #15

banana_giraffe wrote: post #5

For anyone that wants a physical version, SwissMicros makes a calculator based off of Free42: https://www.swissmicros.com/product/dm42

That page says the HP-42S was "widely regarded as one of the most desired calculators ever made". Was it more "desired" than the HP-41C, with all the accessories that you could get for it?

While I own a few HP calculators, my favorite is still the HP-28. Not sure why it isn't as remembered as the other models, but it's the one I still reach for whenever need to calculate anything.

Re: Free42 – An HP-42S Calculator Simulator

#24

Post by zokier » Fri, May 12, 2023, 7:44 AM UTC

nvy wrote: post #19

userbinator wrote: post #14

This IMHO very important information is buried near the bottom of the page: The HP-42S represents numbers with a 12-digit decimal mantissa, and an exponent from 10^−499 to 10^499; Free42 Decimal uses a 34-digit decimal mantissa, and an exponent from 10^−6143 to 10^6144; and Free42 Binary uses native binary floating-point, which on all currently supported platforms is IEEE-754 double precision, with a 53-bit binary ma…

The way you're using "decimal floating point" seems to imply there is a "floating point" that is not "decimal". My understanding is that "decimal", in the context of programming, is a less-precise term to mean floating-point (i.e. encompassing IEEE 754 floats, double- vs single-precision, etc), because they're all binary numbers if you dig deep enough, right? But apparently I am incorrect/underinformed about this. Wh…

IEEE-758 floating point standard defines decimal formats, decimal128 is relevant here, I believe that is what free42 uses: https://en.wikipedia.org/wiki/Decimal128_floating-point_form...

Re: Free42 – An HP-42S Calculator Simulator

#25

Post by rbanffy » Fri, May 12, 2023, 7:44 AM UTC

xlii wrote: post #20

banana_giraffe wrote: post #5

For anyone that wants a physical version, SwissMicros makes a calculator based off of Free42: https://www.swissmicros.com/product/dm42

I can recommend them as I did get one as a gadget. I don’t have a HUGE use for it, but it’s really well done, feels really sturdy and somewhat premium. It was amusing to learn (and re-learn on rare use) more advanced features and programming it. Sure, one can do that with emulator but physicality adds to the fun.

This is something I realized playing with the C64 Maxi. It’s a full sized C64 replica (mine is a VIC 20) and feels very real, even though there is a small ARM board inside it. Physicality is a huge part of the retro experience and a lot of it is the keyboard (which uses a TTY layout).

I wish someone made modern keyboards with Amiga, Atari, Alto, Symbolics, Sun, or DEC LK layouts for use with emulated platforms.

Re: Free42 – An HP-42S Calculator Simulator

#26

Post by stlee42 » Fri, May 12, 2023, 7:51 AM UTC

userbinator wrote: post #14

This IMHO very important information is buried near the bottom of the page: The HP-42S represents numbers with a 12-digit decimal mantissa, and an exponent from 10^−499 to 10^499; Free42 Decimal uses a 34-digit decimal mantissa, and an exponent from 10^−6143 to 10^6144; and Free42 Binary uses native binary floating-point, which on all currently supported platforms is IEEE-754 double precision, with a 53-bit binary ma…

There is a fork with that available.

as posted below:

For anyone that wants a physical version, SwissMicros makes a calculator based off of Free42: https://www.swissmicros.com/product/dm42

That website mentions that they use decimal floating point. Since free42 is licensed under gpl3, they have released the source.

https://github.com/swissmicros/DM42PGM/tree/master/lib

https://github.com/swissmicros/free42/tree/master/inteldecim...

They use Intel's library for decimal floating point: https://software.intel.com/en-us/articles/intel-decimal-floa...

It's still not the real HP-42S with its quirks, but it's nice to have decimal floating point operations.

Re: Free42 – An HP-42S Calculator Simulator

#27

Post by nologic01 » Fri, May 12, 2023, 7:58 AM UTC

This reminded me that after 30 years I need to change batteries on mine.

Re: Free42 – An HP-42S Calculator Simulator

#28

Post by ilyt » Fri, May 12, 2023, 10:19 AM UTC

stlee42 wrote: post #26

userbinator wrote: post #14

This IMHO very important information is buried near the bottom of the page: The HP-42S represents numbers with a 12-digit decimal mantissa, and an exponent from 10^−499 to 10^499; Free42 Decimal uses a 34-digit decimal mantissa, and an exponent from 10^−6143 to 10^6144; and Free42 Binary uses native binary floating-point, which on all currently supported platforms is IEEE-754 double precision, with a 53-bit binary ma…

There is a fork with that available. as posted below: For anyone that wants a physical version, SwissMicros makes a calculator based off of Free42: https://www.swissmicros.com/product/dm42 That website mentions that they use decimal floating point. Since free42 is licensed under gpl3, they have released the source. https://github.com/swissmicros/DM42PGM/tree/master/lib https://github.com/swissmicros/free42/tree/maste…

Aside from keyboard not being quite at HP level (but then which one is? And it is still good), DM42 is entirely better version tbh. Even works with printer!

Weird obscure fact: The printer head for HP calculator printer was still available as new parts as late as 2019, coz it was used in variety of devices, I bought cheap non-working one and just replaced the head

Re: Free42 – An HP-42S Calculator Simulator

#29

Post by ilyt » Fri, May 12, 2023, 10:20 AM UTC

xlii wrote: post #20

banana_giraffe wrote: post #5

For anyone that wants a physical version, SwissMicros makes a calculator based off of Free42: https://www.swissmicros.com/product/dm42

I can recommend them as I did get one as a gadget. I don’t have a HUGE use for it, but it’s really well done, feels really sturdy and somewhat premium. It was amusing to learn (and re-learn on rare use) more advanced features and programming it. Sure, one can do that with emulator but physicality adds to the fun.

I also have DM-16L and I do get some reasonable use out of that, It's programmer's calculator so a bunch of bitwise operations are readily available and have buttons for directly switching modes.

Re: Free42 – An HP-42S Calculator Simulator

#30

Post by tigerlily » Fri, May 12, 2023, 11:30 AM UTC

This app is my daily driver. It was hard to find in the App Store though when I searched for rpn calculators, it was a huge relief to find it.

Little known perhaps but you can tap the display to bring up the main menu. From there you can optionally select a different skin. I use GDW-Modern-i5, a nice clean darkmode with orange highlights.

Edit: actually you have to download new skins from a gallery webpage first via what I can only describe as a tiny embedded web browser you can bring up by clicking "Load..." in the bottom left corner. Truly this must be God's own calculator app.