In this chapter we introduce a basic computer and show how its operation can be puter specified with register is defined by its internal transfer registers, statements. the limirlg The organization and control of structure, the comand the set of instructions that It uses. The design of the computer is then carried out in detall. Although the basic computer presented in this chapter is very small compared to commercial computers, It has the advantage of being simple enough so we can demonstrate the design process without too many complications.
The internal organization of a digital system is defined by the sequence piJ1'j)O&e of rrUcroopera digital tions computer it performs on is capable of data executing stored various in its regislera. miaooperations and, The generalin addition., can be instructed as to what specific sequence of operations it must perform. program. The user of a computer can control the process by means of a A program is a set of instructions that specify the operations,operands, and the sequence by which processing has to occur. The dataprocessing task may be altered by specifying a new program with different instructions or specifying the same instructions with dilferent data.
A computer instruction is a binary code that specifies a sequence of microoperations for the computer. Instruction codes together with data are stored in memory. The computer reads each instruction from memory and places it in a control register. The control then interprets the binary code of the instruction and proceeds to execute it by issuing a sequence of microoperations. Every computer has its own unique instruction set. The ability to store and execute instructions, the stored program concept, is the most important property of a general-purpose computer .