Topic: “The hardwired andmicrocode methods form two radically different approach
ID: 3612451 • Letter: T
Question
Topic: “The hardwired andmicrocode methods form two radically different approaches tocontrol unit design. In your opinion, which approach is better,when we talk in term of performance?
A concise, coherent and tothe point comment is preferred over lengthy comment havingirrelevant details. Your comment must not be more than 5-7 lines.Comments, posted on regular Lesson's MDB or sent through email willNOT be considered. Any request about such an acceptance will not becatered.
Topic: “The hardwired andmicrocode methods form two radically different approaches tocontrol unit design. In your opinion, which approach is better,when we talk in term of performance?
A concise, coherent and tothe point comment is preferred over lengthy comment havingirrelevant details. Your comment must not be more than 5-7 lines.Comments, posted on regular Lesson's MDB or sent through email willNOT be considered. Any request about such an acceptance will not becatered.
Explanation / Answer
Hardwired:
This approach is composed of combinatorialand sequential circuits that generate complete timing thatcorresponds with execution of each instruction.
This approach is time-consuming andexpensive to design also difficult to modify but fast.
Microprogrammed:
Its design is simpler. Problem of timingeach instruction is broken down. Microinstruction cycle handlestiming in a simple and systematic way.
easier to modify
Hardwiredvs. Micro-programmed Computers
It should bementioned that most computers today are micro-programmed. Thereason is basically one of flexibility. Once the control unit of ahard-wired computer is designed and built, it is virtuallyimpossible to alter its architecture and instruction set. In thecase of a micro-programmed computer, however, we can change thecomputer's instruction set simply by altering the microprogramstored in its control memory. In fact, taking our basic computer asan example, we notice that its four-bit op-code permits up to 16instructions. Therefore, we could add seven more instructions tothe instruction set by simply expanding its microprogram. To dothis with the hard-wired version of our computer would require acomplete redesign of the controller circuithardware.
Hardwired:
This approach is composed of combinatorialand sequential circuits that generate complete timing thatcorresponds with execution of each instruction.
This approach is time-consuming andexpensive to design also difficult to modify but fast.