3 ms·

i'am also interested in knowing what a microcode is {wikipedia doesn't have much on this} what's it written in ?

• hga 17y ago
  (Warning, major simplifications here, and mostly from '80s knowledge of the field.) Real microcode is below the level of assembly language. E.g. a horizontal microcode will potentially be controlling the function of each gate or sub-block in a microprocessor. The clock frequency of a synchronous design is generally the time it takes to execute each microcode instruction. So one machine code op code may translate into several microcode operations to achieve the desired outcome. Writing microcode is hard.
  • joezydeco 17y ago
    I don't know what it's like in CS/EE courses today, but back in the day most computer architecture students had to create a simple microcoded-ALU and write both sides of the code. Doing the microcode for those projects was kind of fun, I miss that kind of work sometimes. Now get off my lawn.
    • hga 17y ago
      MIT still does it that way: http://ocw.mit.edu/OcwWeb/Electrical-Engineering-and-Computer-Science/6-004Spring-2009/CourseHome/index.htm http://ocw.mit.edu/OcwWeb/Electrical-Engineering-and-Compute... Back in the late '80s a friend who was taking it told me about a contest of sort they had to the side: you were given an instruction set to implement in hardware and firmware (microcode) and on the day of the contest you were given a program to run on it. The fastest implementations after a day of hacking and tuning won. I notice that the last lab for the above spring 2009 version has a price/performance challenge, which is very apropos to what's hot in this area today (e.g. the ARM, Atom, etc.). You're to minimize the number of gates while still making it run a sample application quickly.