Entry | |
---|---|
R0 | Pointer to VIDC List Type 3 |
R1 | Mode workspace (if mode number), or 0 |
R4 | Bits 0-23: 7 (reason code) |
Bits 24-31: Driver number |
Exit | |
---|---|
R0 | Zero: Mode OK (may be minor adjusts to VIDC list and/or workspace values) |
Non-zero: Mode not OK | |
R4 | 0 |
- | All other registers preserved |
The kernel issues this call to check whether a driver can support a proposed mode. The appropriate driver should respond by checking the mode parameters, setting R0 appropriately, and setting R4 to 0 to claim the call.
For future-proofing, the driver must ensure it checks that the provided VIDC list is a type 3 list.
Instead of calling GraphicsV directly, user software should use OS_CheckModeValid in order to check if a screen mode is valid.