A series covering the basics of microprocessor architecture
Microprocessor instruction pipelining is a hardware implementation that allows multiple instructions to be simultaneously processed through the instruction cycle. This is enabled by the instruction cycle itself as it divides the operations that have to be performed on each instruction into standalone phases (e.g decode, fetch, execute). In the context of the pipeline, we call
The microprocessor (also known as Central Processing Unit(CPU) ) is a computational machine. It executes arithmetic, logical, control and input/output operations. It is programmable and follows the instructions programmed into its memory. Principle of Operation In order for the processor to perform the task required by a particular instruction, it follows a process called the instruction
Instruction Set Architecture (ISA) specifies the instructions that a microprocessor can execute. It can be viewed as a programmer's manual. It clearly defines everything needed for writing either a compiler or machine language program for a microprocessor supporting particular ISA. The ISA itself does not contain hardware implementations details. There can be microprocessors with different
The arithmetic logic unit (ALU) is at the hearth of the microprocessor. It is designed to perform both arithmetic and logical operations on integer binary numbers. Principle of operation The ALU does not need a clock signal as it is a pure combinational digital circuit. The output will change asynchronously in response to change on the
The microprocessor (also known as Central Processing Unit (CPU)) can be defined simply as a calculation machine. It executes predefined operations called instructions. The steps the CPU performs in order to execute an instruction is called an instruction cycle (also known as fetch-execute cycle or fetch-decode-execute cycle). Understanding the instruction cycle is a great starting point for
The program counter (PC) is a register that is part of the central processing unit (CPU). It contains the memory address for the next instruction that has to be executed during the instruction cycle of the microprocessor. Principle of Operation Each instruction cycle begins by accessing the instruction stored at the address that is pointed by
A microprocessor instruction is a description of an operation that has to be performed on a data. The data is called operand. An instruction may have one or more operands. The microprocessor executes instructions in a process called instruction cycle. Each microprocessor is designed to operate on a specific set of instructions defined in its instruction set
Addressing Mode refers to the way the actual location of an instruction's operand is specified. It is used in the decode phase of the instruction cycle to extract the operand of the instruction so the proceeding execute phase can start. The main purpose of having different addressing modes is to provide flexibility when referencing the memory location of
