Games - A-code (11 results)

Level 9 used their own interpretation language, A-code, which was more memory efficient even than plain Z80 assembler. It was developed around 1979, long before the first L9 game appeared, as the Colossal Cave port was intended to fit into 8 KB.

A-code underwent a couple of revisions: there are three distinct versions in all, plus a couple of extensions which form new A-code versions of their own.

The A-code data files were usually incorporated into the executable file for specific machines, together with the interpreter part. Still, even those executables were significantly shorter than pure assembly code files would have been!

This efficiency was partially due to advanced text compression routines that reduced the memory need for text to about 50% of their true length. Infocom's text compression, in comparison, only reduced text strings to about 67% of their real length (abbreviation alphabets notwithstanding).

(From The Level 9 Fact Sheet.)