Froggie (1983) has some interesting code -- and is a topnotch ZX81 game too. Froggie (1983) by Richard Braunton
* Transitions between screens. Simple code, but very effective. See sample code in Transition Effects Code
* Press A Key prompt animation screen at USR 22477
* Goodbye display text effect at USR 18413
It appears to use a traditional game loop (of many, many subroutine Calls). It also demonstrates how to detect keypresses (e.g. see address $4D46).
Attached is an Assembly Language file for the game in ZX-IDE format.
Machine code analyis: Froggie 1983 game
Machine code analyis: Froggie 1983 game
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- froggie-1983.zip
- froggie-1983.asm
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Re: Machine code analyis: Froggie 1983 game
The Goodbye routine uses standard graphics characters placed in REM 8.
I wonder how he originally created this text -- with a special tool, or simply by trial-and-error on a the ZX81 keyboard?
I wonder how he originally created this text -- with a special tool, or simply by trial-and-error on a the ZX81 keyboard?