Graphische Anzeigesteuerung, versehen mit Grenzensuchschaltung.

摘要

A graphics display controller equipped with a boundary search circuit is disclosed. There is provided a mask information generator generating mask information consisting of a plurality of bits in response to control data, at least one bit of the mask information taking non-mask data and the remaining bits thereof taking mask data. Each bit data of the mask information is supplied to the associated one of a plurality of mask gates along with the associated bit data of display data of one word read from a display memory. Each of the mask gates outputs the associated bit data of the display data when the associated mask information bit data is the non-mask data. The output data of the mask gates are supplied to a position information generator wherein the position information relative to a position of a bit taking a predetermined logic level is generated.