Entry | |
---|---|
R0 | Screen mode number to check |
Exit | |
---|---|
If C flag unset, then Screen mode is valid | |
R0 | Preserved |
If C flag set, then Screen mode is invalid | |
R0 | -1 = Screen mode is non-existent |
-2 = Not enough memory | |
R1 | Alternative screen mode to use |
-2 = Unable to select alternative screen mode |
The purpose of this call is to check if it is possible to change to a specified screen mode.
This finds out, whether you may change to a given mode or its invalid, either because the monitor type forbids it, R1 then is the alternative mode, or there’s not enough memory in this case R1 = -2.