Computer Architecture CH01 PDF

Tissemsilt University Faculty of Science and Technology Department of Mathematics and Computer Science Computer Architecture  About This COURSE This course is designed for 2nd year undergraduate computer science students, The aim of this course is to clarify the...

Tissemsilt University Faculty of Science and Technology Department of Mathematics and Computer Science Computer Architecture  About This COURSE This course is designed for 2nd year undergraduate computer science students, The aim of this course is to clarify the operating principle of the computer with a detailed presentation of the computer architecture. Semester 03 Fundamental Teaching Unit 01 Subject Computer Architecture Credits 05 Coefficient 03 Assessment method Exam (60%), continuous assessment (40%) Recommended prior knowledge Boolean algebra, logic gates  Content of This course Chapter 01 Chapter 02 Introduction. Overall architecture diagram. Von Neumann machine VS THE ALU, Buses, Registers, etc. Harvard machine. Internal memory, cache memory, memory hierarchy. Chapter 03 Principles of assembly language, Chapter 04 machine language. The processor, CISC VS RISC. The control and command unit. The MIPS R3000 microprocessor Instruction execution phases. Instruction set, Clock and sequencer. Programming the MIPS R3000 Chapter 05 Notions on interrupts, I/O, system instructions of the MIPS R3000.  Chapter 01 Introduction The concept of computer architecture Von Neumann machine VS Harvard machine. The concept of computer architecture Computer Architecture is concerned with the structure and behaviour of the computer, including information formats, the instruction set, the processor, memory and addressing techniques. The concept of computer architecture The Architecture represents the organisation of each unit and their interconnections. The choice of the architecture depends on: Performance. Cost. Efficiency. Simplicity of design. Diversity.  The concept of computer architecture A digital computer is a machine that executes instructions given to it. A sequence of instructions describing how to perform a certain task is called a program. The electronic circuits of the computer can recognize and directly execute a limited set of simple instructions into which all its programs must be converted before they can be executed. These basic instructions are rarely much more complicated than add two numbers, check a number to see if it is zero, etc. The concept of computer architecture Together, a computer’s primitive instructions form a language in which people can communicate with the computer. Such a language is called a machine language. The people designing a new computer must decide what instructions to include in its machine language. Usually, they try to make the primitive instructions as simple as possible consistent with the computer’s intended use and performance requirements, in order to reduce the complexity and cost of the electronics needed. The concept of computer architecture Because most machine languages are so simple, it is difficult for humans to use them. This problem led to a way of structuring computers as a sequence of abstractions, each abstraction is built on the one below it. In this way, the complexity can be controlled and computer systems can be designed in a systematic, organised way. The concept of computer architecture The problem can be approached in two ways: both involve designing a new set of instructions that are more convenient for humans to use than the set of built-in machine instructions. Taken together, these new instructions also form a language, which we will call L1, just as the built-in machine instructions form a language, which we will call L0.  The concept of computer architecture TO execute a programme written in L1, first replace each instruction in it with an equivalent sequence of instructions in L0. The resulting program consists entirely of L0 instructions. The computer then executes the new L0 program instead of the old L1 program. This technique is called Translation. OR we write a program in L0 that takes programs in L1 as input and executes the equivalent sequence of L0 instructions directly. This is called Interpretation. The concept of computer architecture Von Neumann VS Harvard machines. Historically there have been 2 types of Computers: 1. Fixed Program Computers Their function is very specific and they couldn’t be reprogrammed, e.g. Calculators. 2. Stored Program Computers These can be programmed to carry out many different tasks, applications are stored on them, hence the name.  Von Neumann VS Harvard machines. Modern computers are based on a stored program concept introduced by John Von Neumann in 1945, in this architecture programs and data are stored in a separate storage unit called memories and are treated the same. This novel idea meant that a computer built with this architecture would be much easier to reprogram, it was later known as Von- Neumann architecture, It is also known as Instruction set architecture.  Von Neumann VS Harvard machines. Von Neumann bottleneck: instructions, and data both are stored in the same memory and buses are used to fetch instructions and data. This means the CPU cannot read the instruction and read/write data simultaneously. These factors affect the performance of the CPU.  Von Neumann VS Harvard machines. Harvard Architecture is the computer architecture that contains separate storage and separate buses for instruction and data. It was basically developed to overcome the bottleneck of Von Neumann’s Architecture. The main advantage of having separate buses for instruction and data is that the CPU can access instructions and read/write data at the same time.  VON NEUMANN ARCHITECTURE HARVARD ARCHITECTURE It is ancient computer architecture based on It is modern computer architecture based on stored program computer concept. Harvard Mark I relay based model. Same physical memory address is used for Separate physical memory address is used instructions and data. for instructions and data. There is common bus for data and instruction Separate buses are used for transferring data transfer. and instruction. Two clock cycles are required to execute An instruction is executed in a single cycle. single instruction. It is cheaper in cost. It is costly than Von Neumann Architecture. CPU can not access instructions and CPU can access instructions and read/write at read/write at the same time. the same time. It is used in personal computers and small It is used in micro controllers and signal computers. processing.