Atari Calculator for the Commodore 64

[norbert_kehrer]

In 1979 Atari shipped a program called "Atari Calculator" for the Atari 800 computers.

It provides the functionality of powerful, programmable scientific and financial calculators

on the Atari home computer.

 

The Atari Calculator was written by Carol B. Shaw at Atari. I reverse-engineered her program

and moved it to the C64. The I/O routines for the Atari were replaced by equivalent C64 subroutines.

The complete Atari floating-point library, which is heavily used by the Calculator program, and the

Atari 800 character font also were ported to the Commodore computer.

 

Those who are interested and have a C64 (or an emulator) can read more and download the

C64 program at my homepage: http://web.utanet.at/nkehrer/

 

Greetings

 

Norbert

[+Stephen]

Cool. Any idea how that program gets more precise values than BASIC does, if both are relying on the built in FP library?

[norbert_kehrer]

Actually, I am sure that the BASIC of the Atari 800XL gives the same results as Atari Calculator (e.g. "PRINT LOG(1)" results in "0" both in BASIC and in Calculator). I think, that only the first versions of the Atari 800 BASIC (Rev. A?) and of the floating-point ROM had different rounding methods and showed values like "4.60517018E-10" for LOG(1). But note, that some people here in the forum already stated, that the rounding methods used in the later BASIC versions (and also in Calculator) are not really correct also.

 

Norbert

[+Stephen]

There are some comparisons on this site http://wiki.strotmann.de/wiki/Wiki.jsp?page=Atari%20Calculator that showed the calculator as being more accurate.

 

But now that I look again, yes, they are comparing BASIC Rev.A from 1979, and Turbo BASIC 1.4.

[fibrewire]

This calculator, correct?

 

http://www.atarimania.com/game-atari-400-800-xl-xe-calculator_28613.html