The trend of the computer architecture is to adapt the computer dynamically to the applications. There are some available computers that provide the application adaptability by using WCS (writable control store). WCS, in general, is fast in access but expensive. In a multiprogramming environment, however, using WCS may produce the operating system overhead, therefore total speed may decrease in some cases.
Computer organization which provides user-microprogramming using MM(main memory) is suggested in this thesis. Such an organization has advantages of flexibility, low cost, similarity with ordinary microprogrammed computer in comparison with the computer using WCS. It also can increase the system speed in some cases, especially in multiprogramming environments.
CRIMM, which is developed for this thesis research, has the user-microprogramming facility using MM. Overall organization and some special features of CRIMM are described in detail in this thesis. Because CRIMM is modified from CRIROS, which is a microprogrammed computer and also developed by us, conventional microprogrammed computers may be made user-microprogrammable using MM by adopting these special features.
Evalution of user-microprogrammable computer using MM in comparison with using WCS is also made in this thesis.
