A memory management unit and cache controller for the MARS system

For large caches, the interaction between cache access and address translation affects the machine cycle time and the access time to memory. The physically addressed caches slow down the cache access due to the virtual address translation. The virtually addressed caches is faster, but the synonym problem is difficult to handle. By some software constraints and hardware support, the virtually addressed physically tagged caches can achieve the same speed as traditional virtually addressed cache and solve the synonym problem. The design of delayed miss signal makes the TLB access depart from the critical path of the cache access. A simple method to solve the TLB coherence is implemented in this chip and only a little hardware is required