CP/M 3 hardware error codes
Normally, if a hardware (or similar) error is encountered CP/M will print a message describing the
error and then quit to the command prompt. In CP/M 3, BDOS function 45
can be used to modify this behaviour, so that error codes are returned to the program instead.
The codes returned are in the H register:
0 - Software error (eg file not found)
1 - Select error (cannot access drive)
2 - Disc is read-only
3 - File is read-only
4 - Invalid drive
5 - File already open
7 - Password error
8 - File already exists
9 - Filename contains ?
10 - Wheel protection error (ZPM3)
