| 摘要 |
A horizontal scrolling apparatus that provides scrolling on a character-by-character basis including a screen memory and associated visual attribute memory having associated therewith a scroll control memory for storing at least one bit for controlling horizontal scrolling. A latch controls writing into the scroll control memory to provide an enable bit therein, only in those locations corresponding to characters that are to be scrolled. An offset number is stored in an offset register, which number is variable under computer control. Operation of an adding circuit is responsive to sensing of the enable bit for adding the offset number to the present screen address to provide an offset address. The offset address is coupled to the video memory for display of the character associated with the offset address in the screen address position.
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