(An) emulation oriented CPU design

Abstract

After the first 8080 was introduced in 1973, various types of MOS microprocessors are used in many applications. The more microprocessors are used the faster microprocessors are needed for special applications. In this thesis, the Am 2900 series which is easy to microprogram and has two addressing ALU feature has chosen to emulate M6800, n-MOS 8-bit processor which has several addressing modes. For the microprogram development, a microassembler is designed and implemented is NOVA 840 computer in order to make easy converting microcodes to ROM image. As a result 262 x 35 bit control memory is used to interpret M6800 instructions and additional custom designed instructions. The microprograms are simulated on NOVA 840 to conform the correctness before implemented on wire-wrapping board. The 2-5 time speed improvement is achieved and an 8-bit unsigned multiplication "MPY" is implemented. Also an additional addressing scheme, one-level indirect address, is implemented.