Integer BASIC - Relationship To Applesoft BASIC

Relationship To Applesoft BASIC

The most frequently cited flaw of Integer BASIC was, as one might expect from the name, that its variables were all 16-bit integers and it was very difficult to write a program that could do calculations using floating point numbers, or even integers outside of the range -32768 to +32767. It was therefore very difficult to write financial or math programs.

Apple Computer licensed a more full-featured (but also much slower) BASIC from Microsoft soon after the Apple II was released in 1977, introduced some tweaks, named it Applesoft BASIC, and included the second version of it in the ROMs of the Apple II Plus, which was released in . Integer BASIC was relegated to a file on the system floppy disk that Apple II Plus users could load into a RAM card for backward compatibility, if needed. Applesoft BASIC was included in the ROMs of all Apple II models from the Apple II Plus forward, and eventually became the platform for far more programs than Integer BASIC. However, loading the Integer BASIC language from floppy disk is possible even on the latest models of the Apple II line, should the need or desire arise.

Integer BASIC's speed advantage was partly because floating-point calculations are more complex and thus inherently slower on the Apple's 6502 CPU than binary calculations. That CPU doesn't have a hardware floating point unit, so all floating point has to be performed indirectly, in software. Applesoft BASIC uses floating point for all numerical operations, even in cases where integer would suffice. The speed advantage was also partly due to some syntax checking being performed by Integer BASIC at entry-time, as well as numbers being converted to binary form at that time, rather than these things being done at run-time. (A popular speed optimizing technique in most interpreted BASICs — including Applesoft — is to put all frequently used constants into variables, because fetching the variable's value is faster than converting a number from text — a difference which becomes significant, given perhaps hundreds of iterations. This method is superfluous in Integer BASIC.)