STOP
Check if key/stop key is pressed
| Function | Address | Vector | Description |
|---|---|---|---|
| STOP | FFE1 | 0328 | Check if key/stop key is pressed |
This routine checks for either the RUN/STOP key or certain other keys are pressed.
Check for RUN/STOP key pressed
If the key was pressed during a UDTIM call, this call returns the z flag set. In addition, the channels will be reset to default values.
Example:
Check for STOP key pressed
JSRSTOP
BNEstopNotDown
JMPstopDownJump to code to handle STOP
stopNotDownContinue further processing
In the above example if the STOP key is pressed we jump to the method stopDown.
This method could reset your application, cancelling some lengthy operation.
Check for other keys
If the stop key is not pressed then the z flag will be clear and the accumulator will be set to one of the following keys located on the same keyboard column as the stop key:
| C64 key | Accumulator | Vic-20 key | Accumulator |
|---|---|---|---|
| 1 | 0xFE | Cursor Down | 0x7F |
| Left arrow | 0xFD | / | 0xBF |
| CTRL | 0xFB | , | 0xDF |
| 2 | 0xF7 | N | 0xEF |
| Space | 0xEF | V | 0xF7 |
| Commodore | 0xDF | X | 0xFB |
| Q | 0xBF | Left Shift | 0xFD |
If no key is down in the STOP column, the routine returns 0xFF on both machines.
Last modified October 19, 2021: Remove weighting so left index is now alphabetical (cbe7734)