Difference between revisions of "VDU 22"

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Revision as of 19:13, 8 March 2015

Selects a display MODE.

VDU 22
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.

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.

-- beardo 20:52, 10 November 2007 (UTC)