Display advance system for a word processor

DETAILED DESCRIPTION The present invention provides a display advance system for a word processor having a video screen that displays only a section, typically one-third, of a full page of text stored in a memory.
When a DISPLAY ADVANCE control key is depressed, a determination is made as to which section of the page follows that which is currently displayed.
The initial address of the memory area storing that next text section is derived, and is used to generate a video display of the new section beginning at the next video frame.
Advantageously, the next section of text is determined by reference to the current position of a sursor that is displayed on the screen.
A program, under microprocessor control, examines the current cursor row position and determines whether this position lies in the top, middle or bottom one-third text section.
The same program then relocates the cursor to the bottom row of the next text section, and enters into a buffer the memory address in which the top line of the new text section is stored.
Beginning with the next video frame, this "top line of text" address is used to direct readout from the memory of the new section of text for utilization by the video generation circuitry.
As a result, the new one-third text section appears on the screen.