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OS_CheckModeValid
Programmer's Reference Manuals
» Part 15 – SWI Calls
» OS
» OS_CheckModeValid
OS_CheckModeValid
(SWI &3F)
| 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 | |
Use
The purpose of this call is to check if it is possible to change to a specified screen mode.
Notes
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.