8K Machine Code Keyboard Scanning

Bernard Puerzer’s program for scanning the ZX80 keyboard (Machine Code Keyboard Scanning Program) was written for the 4K ROM, His program served as the occasion to give the same ability to read the keyboard to 8K ROM users. This required adaptation since the programs are not automatically transferable. One of the problems was to get around the differences in the way that the index registers are used. This program avoids that problem. Further, it adds a WAIT loop which keeps the screen dark after ENTER is pressed and then prints the keyboard entry following ENTER.