Editing Interpreter (computing) (section)

=== Microcode ===
{{main|Microcode}}
Microcode is a very commonly used technique "that imposes an interpreter between the hardware and the architectural level of a computer".<ref name=Kent2813>{{cite book |last1=Kent |first1=Allen |last2=Williams |first2=James G. |title=Encyclopedia of Computer Science and Technology: Volume 28 - Supplement 13 |date=April 5, 1993 |publisher=Marcel Dekker, Inc |location=New York |isbn=0-8247-2281-7 |url=https://books.google.com/books?id=EjWV8J8CQEYC |access-date=Jan 17, 2016}}</ref> As such, the microcode is a layer of hardware-level instructions that implement higher-level [[machine code]] instructions or internal [[state machine]] sequencing in many [[digital processing]] elements.  Microcode is used in general-purpose [[central processing unit]]s, as well as in more specialized processors such as [[microcontroller]]s, [[digital signal processor]]s, [[Channel I/O|channel controllers]], [[disk controller]]s, [[network interface controller]]s, [[network processor]]s, [[graphics processing unit]]s, and in other hardware.

Microcode typically resides in special high-speed memory and translates machine instructions, [[state machine]] data or other input into sequences of detailed circuit-level operations. It separates the machine instructions from the underlying [[electronics]] so that instructions can be designed and altered more freely. It also facilitates the building of complex multi-step instructions, while reducing the complexity of computer circuits. Writing microcode is often called '''microprogramming''' and the microcode in a particular processor implementation is sometimes called a '''microprogram'''.

More extensive microcoding allows small and simple [[microarchitecture]]s to [[Emulator|emulate]] more powerful architectures with wider [[word length]], more [[execution unit]]s and so on, which is a relatively simple way to achieve software compatibility between different products in a processor family.