The microprogram is the algorithm of a microprogram control station in a processor for controlling its arithmetic logic unit. Microprograms are created by micro- programming. These microinstructions of a microprogram can be arranged in an addressable order and provided in a read only memory, the so-called micro- program memory. The microinstructions contain binary coded instructions with a fixed number of bits for activating and deactivating logical functional units. In this manner, the microprogram control unit determines with the aid of the micro- program, which shifts the sequence in which the implementation of machine instructions required for an arithmetic logic unit. Under certain circumstances, switching operations are not initiated immediately in full by the microcode, but by downstream nano programs that are implemented as nano code. The totality of the microprogram memory in binary coded form micro instructions the micro code.
In addition, the micro instructions including a memory addressing inherent requirement that position of the next microinstruction to be controlled for the cyclic, the cyclic execution of the control schedule can be calculated with the aid of. In this way it is possible to execute microinstructions in the microprogram, not only in ascending address order with a simple jump distance, but also in addressing sequences, the absolute, relative and conditional jumps can include addressing. Thus, there is the possibility of a redundance- free as possible structuring of the schedule with respect to repetitive sequences of microinstructions. Thus, there is the possibility of the limited existing microinstruction memory in a CPU for programming of machine instructions in the control language of microinstructions to as efficiently as possible.
The microprogram can be created directly in the form of binary encoded microinstructions. However, tools such as micro- assembler can be used for micro- programming to automate the control statements of the microinstructions of a microcode program from a readable representation in the confusing binary form microinstruction translate. At the same time can be managed with the microassembler the microprogram memory and the inherent memory addressing order a programmed sequence of micro instructions flexible. The creation of a microprogram to control a virtual computing unit is mediated by the microcode simulator Micro didactic manner.