The addressing mode part of the machine instruction format allows to specify whether the OPERAND value is a direct data Or It is an indirect referencing. Introduction to computer systems architecture and programming J. The addressing mode for the machine instruction specifies the rules for the CPU while operating on the OPERAND. The main advantage that this architecture offers over the others is that now you can store your programs into. The stored program concept was first introduced by John von Neumann in 1945, and it has been the basis of every computer ever built since then. The first part indicates the addressing mode, the second part OPCODE specifies the operation to be performed and the third part OPERAND either data or address of the data. Stored-program concept is the fundamental idea upon which all modern computers are based. In microprocessor architecture, the instruction format is a standard machine instruction format that CPU can decode and execute.ĭepending upon the instruction type, the pattern of bits in the machine instruction format consist of three parts. It provides the information about the operand whether it contains either the data or address of the data. The output and production of the architecture industry has been revolutionized, and continuously developed through technology and advancements in computer software. The addressing mode is represented by a single bit in the instruction format. Architecture programs and design software.
In simple words, the addressing mode is the field ( single bit ) in the instruction format that directs the processor regarding how to locate the data that is to be operated by the CPU.