Assembly Routines

Tutorial by Luca Bordoni

A collection of useful machine code routines for your ZX Spectrum projects, fully relocatable. A basic knowledge of the Assembly main concepts and the ZX Spectrum memory management is recommended.


Description — starting from the upper left corner attribute address (22528), for each character block (32 per row) and for each row (24 in total), the colours will decrease their values from paper black / ink bright white (71) to paper black / ink bright black (64).


Description — the first routine reads the attributes starting from the upper left corner (22528), storing the values in a specific memory address (63999 in this example) for the total length of the attributes (768). A second inverse routine restores the values on the screen.