Difference between revisions of "VDU 22"
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== Description == | == Description == | ||
| − | + | <code>VDU 22,n</code> changes the display to <code>MODE n</code>. For a list of display modes, see <code>[[MODE]]</code>. | |
| − | <code>VDU 22,n</code> changes the display to <code>MODE n</code>. | ||
* The [[OSBYTE &84|start of display memory]] is moved, but the current [[Paged ROM|language]] is not informed. | * The [[OSBYTE &84|start of display memory]] is moved, but the current [[Paged ROM|language]] is not informed. | ||
| Line 38: | Line 37: | ||
The start of display memory for a given <code>MODE</code> can be found without changing to that <code>MODE</code>, with [[OSBYTE &85]]. | The start of display memory for a given <code>MODE</code> can be found without changing to that <code>MODE</code>, with [[OSBYTE &85]]. | ||
| − | + | {{MODE}} | |
| + | [[User:Beardo|beardo]] 20:52, 10 November 2007 (UTC) | ||
Latest revision as of 19:57, 12 October 2016
Selects a display MODE.
| Syntax | VDU 22,<numeric>
|
| Character stream (hex) | 16 <mode>
|
| Description | Changes the display to MODE <mode>
|
Description
VDU 22,n changes the display to MODE n. For a list of display modes, see MODE.
- The start of display memory is moved, but the current language is not informed.
- The CRTC, video ULA and address translation latches are reprogrammed, taking into account the
*TVsetting. - Changing to a graphics mode, the actions of
VDU 20are performed: - The text and graphics windows are reset to fill the whole display.
- The text and graphics cursors are uncoupled.
- The text window (the whole screen) is cleared.
- Paged mode is turned off.
- The text cursor is made visible and returned home.
Since the display memory may 'explode' without the current language being informed, VDU 22,n can corrupt user memory in the I/O processor. Mode changes must therefore be made through the language (for instance in BASIC, by the statement MODE n.)
When user memory is separate from display memory (that is, when *SHADOW mode, a Tube coprocessor or the Archimedes is in use) then mode changes can be made by either method.
The start of display memory for a given MODE can be found without changing to that MODE, with OSBYTE &85.
| Screen display MODEs |
|---|
|
MODE 0 | MODE 1 | MODE 2 | MODE 3 | MODE 4 | MODE 5 | MODE 6 | MODE 7 |
beardo 20:52, 10 November 2007 (UTC)
