Turbo-BASIC XL

Turbo -BASIC XL is developed for Atari XL / XE BASIC dialect that is abwärtskomptabel to Atari BASIC and is characterized mainly by a much faster processing speed and commands for structured programming. Developed the language of Frank Ostrowski, who later developed for the company GfA system technology the interpreter GfA BASIC. Was published Turbo BASIC XL first time in 1985 as a listing of the month in the magazine Happy Computer ( Markt & Technik Verlag), and later a compiler has been published.

Compared to Atari BASIC

Backward compatibility with Atari BASIC

Turbo -BASIC XL implements all commands of the Atari BASIC and uses the same file format. Therefore Atari BASIC programs can be run directly under Turbo -BASIC XL usually without adjustment, but run about four times faster. This can have the consequence that about a program written in Atari BASIC game on Turbo -BASIC XL is no longer playable.

Another cause of the incompatibility of different memory allocation. Turbo -Basic XL is about twice as large as Atari BASIC with almost 16 KB. Nevertheless, under Turbo -Basic XL are about 34 KB program memory available. This is approximately 2 KB more than in Atari BASIC with DOS, since Turbo -BASIC is stored partly in memory areas that are not used by Atari BASIC. However, programmers use these memory areas often for subroutines in machine language. Such programs are limited to get under Turbo -BASIC XL and running.

Structured Programming

A significant improvement over Atari BASIC is the introduction of commands for structured programming. So REPEAT ... UNTIL, WHILE ... WEND, DO ... LOOP and IF ... ELSE ... ENDIF were introduced. With PROC name ... ENDPROC one can define subroutines that are called with EXEC name.

In Turbo -BASIC XL, a program can be written completely without GOTO statements. The few exceptional cases in which nevertheless a direct jump is needed in the program, can be caught with GO # label.

One can clearly see the precursor to GfA BASIC in Turbo -BASIC XL.

Graphics commands

Already Atari BASIC commands had to set the graphics mode and draw points and lines. With Turbo -BASIC XL can draw beyond even circles and ellipses, fill closed areas and spend texts on the graphics screen. With BPUT and bGet, memory blocks, such as images, are stored on an external storage medium or loaded from there.

Also Turbo -BASIC XL does not have commands for programming Player Missiles ( sprites), so that one is dependent on PEEK and POKE instructions as Atari BASIC. After all, there is a MOVE command to move entire blocks of memory, the somewhat simplified at least the programming Player Missiles.

DOS commands

With commands like DIR, DELETE, RENAME, LOCK or UNLOCK you can access on Turbo -BASIC XL directly to the floppy disk drive, without cryptic as in Atari BASIC XIO Views (extended input / output, a special command among Atari BASIC ) use to need. In particular, that one can look at the directory of the disk directly facilitates the work considerably in program development.

General commands and functions

In Turbo -BASIC XL, you can work directly with hexadecimal numbers, and there are powerful commands for searching strings are available. There are also a series of commands and functions that are to be programmed in Atari BASIC only detours as DIV, MOD, CLS (Clear Screen) or PAUSE.

Advanced editor

Turbo -BASIC XL uses the well-known Atari -BASIC editor, but this proposal was greatly expanded. By default, loops and IF -THEN -ELSE blocks are highlighted by the engagement by two spaces. Programs are easier to read. For the output of listings on the printer or other external devices, however, this function can be set down. By pressing one of the console keys (Option, Select, Start) screen output of program code can be slowed down.

Additionally there are commands that all program blocks can be deleted or renumbered, with DUMP, the variable table to be output. With TRACE, the line numbers are issued during program execution, programs can be debugged more easily.

AUTORUN.BAS

A Basic program, which is stored under the name " AUTORUN.BAS " on the disk will be automatically loaded and started from Turbo -BASIC XL at boot time. Under Atari Basic assistance programs in machine language were necessary for this. For the compiler (see below), the compilations had to be stored for this purpose under the name " AUTORUN.CTB ".

Compiler

1986 was published Computer Turbo BASIC XL compiler in the first Atari-XL/XE special issue of the journal Happy. This compiled programs run again on average three times faster than under Turbo -BASIC XL. Compared to Atari BASIC thus a gain in speed by a factor of 10 to 12 was in the benchmarks Turbo BASIC XL compiler results faster than any available 1986 commercial BASIC compiler for the Atari home computers.

Dissemination

Turbo -BASIC XL is one of the most successful programming languages ​​and by Atari BASIC probably the most widely used BASIC dialect for the Atari home computers. The commercial successor to Atari BASIC ( BASIC A , BASIC XL and BASIC XE) of Optimized Software Systems (OSS ) were to some extent by the range of commands significantly more powerful and comparatively fast as Turbo -BASIC XL, but could be these programming limited to use commercial application development, since it was not even a runtime library for this compiler and not for the BASIC A. In addition, these programming cost between 80 and 100 U.S. dollars, while there were Turbo -BASIC XL and compiler for practically nothing.

Trivia

With a length of 18108 bytes Turbo -BASIC XL is one of the longest programs that has ever been published by the magazine Happy Computer for typing, usually there was a size limit to approximately 10 KB. Since the programs were printed hexadecimal, you had to enter including checksums more than 40,000 characters for the interpreter. Compiler and runtime were together almost as extensive.

The listing of the interpreter was published three times a total of Happy Computer. For the first time in issue 12/1985, then in the first Atari Special Edition (1986 ), and finally again in the 2nd Atari Special Edition (1988).

By publishing as Abtipplisting was Turbo -BASIC XL in the Atari scene incorrectly as public domain. An official release by Markt & Technik there was never, however. However, since the late 1980s pretty much every Atari User a copy of Turbo -BASIC XL had - of which typed the least the program or had acquired a reader service diskette - is likely to Turbo -BASIC XL the most widely pirated program for the Atari XL / be XE.

Frank Ostrowski developed his BASIC interpreter originally on an Atari 800 This version was not published (without additional XL) only in 1986 under the name Turbo -BASIC v1.4, but it is only of historical importance, since at the time the Atari 800 machines were only sparsely in use, also you only have about 23 KB of memory for its own programs freely.