Jump to content

SciCalc 2600


Recommended Posts

Hi everybody,


I'm developing a scientific calculator for the 2600, in the style of a Casio FX-82, or a TI-35.


For now, it can manage numbers up to 11 digits (2 decimal), both positive and negative, and can perform the four basic operations and square roots. Also, will manage overflow (for now, only for multiplication).


At least I think I'm going to also add some memories, basic trigonometric calculations, logarithm operations and maybe extend it to manage any arbitrary number of decimal digits.


Its use is intuitive, use the left joystick to move the cursor over a number or operation, and fire to select it, something like a real calculator.


This is the first thing I develop for the Atari 2600, so I'm using Batari Basic, but I have experience with assembly programming, so I'm coding some of the math routines in 6202 assembly, so they can run fast enough.


Additions, subtraction and some parts of multiplication are already coded in assembly. Meanwhile, an hourglass can appear if an operation can take some time to perform.


If the right difficulty switch is set to A, the display is not updated while performing calculations, and they run many times faster. I'd like to know what appears if it's used on a CRT screen, as don’t have any available.


I have attached the first prototype (PAL60 / NTSC).



  • Like 3
  • Thanks 1
Link to comment
Share on other sites

so no one else went wozers over this, the virus, crazy times- I'm really impressed.  So you wrote the calculator program which functions thru the tia and you literally can do calculations on the vcs. theres a basic 4k calculator rom somewhere on here, i knew this was done but yours is advancing on that. 

Edited by chewy
  • Like 1
Link to comment
Share on other sites

*if you can clone the TI-35 I will move your rom from DEMOS--->Tools--->Calculators to my TEXAS INSTRUMENTS folder and add a new folder SCIENTIFIC CALCULATORS were i will put your homebrew, along w/ where i keep the "Fall Down" game, which originated on a TI-83, so in the TI-83 folder would be fall down and in the TI-35 folder, would be SciCalc2600, for example.  My harmony cart folders are complex, but organized.  

Link to comment
Share on other sites

We'll be checking out SciCalc on tomorrow's (Sun May 17) ZeroPage Homebrew stream LIVE on Twitch at 11AM PT | 2PM ET | 6PM GMT! Hope everyone can watch!







Edited by ZeroPage Homebrew
  • Like 1
Link to comment
Share on other sites

Thank you everybody for your comments.


I have been working a bit in this project, an I  have attached a new version. In this version, there is overflow control for all operations, and it can also calculate square roots and logarithms. 


Square roots are slow because they use internally a lot of divisions, and that operation isn't optimized at all for now. Anyway if updating the screen is disabled, they don't take very long.


Logarithms, as they are calculated partially based on tables, for now they aren't 100% exact. I'll expand that tables as much as possible using the empty space in the ROM when all the code is finished. Most of the code for logarithms will be used also for sin / cos / tan calculations.


Next work I'm go to do is code exponentiation, and optimize division. 




  • Like 1
  • Thanks 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...