This paper describes the IC design language BIT‐I implemented on a personal computer, and the bit‐map CAD system employing the language. The system is composed of several programs covering the mask pattern design, design rule check, extraction of circuit parameters, function simulations, and conversion of data formats. Actual data processing in the program of design rule check and extraction of circuit parameters consists of the combinations of basic logic operations. The basic logic operations are described in the subprograms and their combinations are described in the main program. Therefore when new programs are to be developed for different water fabrication process or different devices, only the development or modification of new main programs can manage them.

This paper describes the photomask pattern data processing system (MAPPS-111) for MOS ICY using a general-purpose microcomputer, MAPPS-I11 is composed of figureinput and edit program, check program using design rules, logic extraction and simulation program, and conversion program into drawing format. Photomask patterns for layers are stored in the main memory as bit-maps, and the major data processings are performed by bit operation, logic operation and counting. A s a result, a systematic real-time data processing of the photomask pattern is realized by a microcomputer. MAPPS-111 was developed for MOS IC with four photomasks, but it can be expanded to the process using a larger number of masks and to bipolar or CMOS IC.