| 摘要 |
PURPOSE:To detect the boundary of a painting out area at high speed, by discriminating bit information at the retrieval start point of a painting out boundary, and generating bit position information in relation between data in a display memory and mask information. CONSTITUTION:A sequencer 1 inputs a painting out instruction and the information of a boundary retrieval start point from a host processor, and decides the bits (1) and (0) of the retrieval start point. At this time, data of 16 bits of one word having the bit designated at the boundary start point is read out from the display memory 8 via a memory control circuit 7, and it is supplied to mask gates (5-0-5-1), respectively, and next, the position data consisting of four bits of a designated bit are written on mask registers 2 and 3, and the content of each register is sent to a mask information generation circuit 4. The mask information (4-0-4-F) of 16 bits are sent to respective gate 5, and only one of outputs of the gates 5 is sent to a position information generation circuit 6 as (1) when the data at the retrieval start point is set at (1), and the circuit 6 generates the position information corresponding to retrieval direction information from the sequencer 1. |
