Introduction to Microprocessors
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The document provides an introduction to microprocessors, including: - A microprocessor is an integrated circuit containing millions of transistors that can process data according to programmed instructions. Examples include Intel, AMD, and PowerPC processors. - The three basic functions of a microprocessor are to fetch instructions from memory, decode what the instructions mean, and execute the instructions. - Key components include the ALU for arithmetic/logic operations, control unit for flow control, and registers for temporary storage. - Early Intel processors included the 4-bit 4004 and 8-bit 8008, while the 16-bit 8086 was the first in the x86 architecture still used today.
Introduction to Microprocessors
- 1. INTRODUCTION TO MICROPROCESSORS Compiled by: Seble N.
- 2. What is Microprocessor? Is a clock-driven semiconductor made of millions of microscopic array of electronic circuits and electronic components (resistors, capacitors, inductors…) that are diffused or implanted to surface of small silicon chip its basic purpose is to take input, process it and then provide appropriate output Examples Intel processors, AMD , PowerPC … 2
- 3. Function of microprocessors A microprocessor performs three basic steps: First, it fetches an instruction from memory, Second, it uses decoding circuitry to determine what the instruction means (i.e., identify the operations and the devices involved in it) and Third, it executes the instruction 3
- 4. Components of microprocessor ALU (Arithmetic/Logic Unit) performs all arithmetic and logic operations Control Unit Interprets the instructions and generates various timing and control signals it controls the flow of data between the μ-processor and memory & peripherals Registers A register is a very small & very fast memory that is built into the CPU in order to store the current data and instructions which are being executed by the CPU 4
- 5. Modes of Processing Real Mode One program at a time Protected Mode Can run more than one program concurrently and protect them from each other Virtual Mode The processor can swap portion of the memory to the hard disk; in this way programs running concurrently will have more space to operate 5
- 6. Characteristics of microprocessors Instruction set the set of instructions that a microprocessor can understand or execute Word length refers to the number of bits a processor can process at a time Eg. a 4-bit processor means the ALU can perform a 4-bit data operation at a time the longer the word length is the more powerful the processor is and can process data at a faster speed as compared to processor with shorter word length 6
- 7. Characteristics of microprocessors Speed measured in HZ = 1cycle/second Some processors may complete a single instruction per cycle, or may take one or more cycles a 2 GHZ CPU may compute 2 billion instructions per second, if it is able to complete a single instruction in a single cycle but if it takes 2 cycles to complete a single instruction then it is only able to compute 1 billion instructions per second Cache Size The size of the cache memory 7
- 8. Characteristics of microprocessors … Size of registers refers to the number of bits a microprocessor’s register can hold at a time the size of addressable memory is often determined by the width of registers Data bus width Refers to the number of bits a data bus can carry at a time 8
- 9. Classes of microprocessors 1. Complex instruction set computer (CISC) Often contain instructions that perform several different tasks at a once Ex: Intel Processors 2. Reduced instruction set computer (RISC) are made according to the function in which the microprocessor can carry out small things in a specific command In this way these processors completes more commands at a faster rate is simpler, smaller and faster Ex: PowerPC and ARM's Cortex chips 9
- 10. Evolution of Microprocessors Computing technologies based on vacuum tubes and transistors In 1959, Fair child semiconductors invented the first integrated circuit In 1968, Gordan Moore, Robert Noyce & Andrew Grove founded Intel(Integrated Electronics) In 1971, the first microprocessor, Intel 4004 was released In 1972, Intel released the first 8-bit microprocessor Intel 8008 In 1976, MOS technologies introduced the Motorola 6502 an 8-bit processor, used in Apple I and II In 1981, the first PC was created by IBM using intel’s 8088 microprocessor Several companies like Intel, AMD, IBM, ARM, Motorola… make general purpose processors that are designed for personal computers, laptops, mobile devices and large central servers 10
- 11. Intel microprocessors Intel is generally regarded as the company that sets the benchmark for others to follow From the earlier Pentium and Centrino microprocessors to the Core 2, Core i series Atom chips for mobiles The high-end Itanium and Xeon processors for server applications Over 90% of laptops use Intel microprocessors HP, Dell, Apple, Samsung, Sony, Toshiba … 11
- 12. Top CPU manufacturers Intel AMD Qualcomm Mediatek NVIDIA IBM Samsung Motorola Hewlett-Packard (hp) Dell Acer … 12
- 13. Intel microprocessors Intel 4004 Intel 8080 Intel 8085 Intel 8088 Intel 8086 Intel 80286 Intel 80386 Intel 80486 Pentium Pentium II and III Dual Core/ Core Core i3, i5, i7 13
- 14. Intel microprocessors … 4-bits processors Intel 4004 1971- the first commercially available processor as well as the first complete CPU on a single chip a 4-bit processor: able to operate on 4 bits of data at a time 4-bit data bus had 2,300 transistors clock speed of 108KHZ 640 bytes addressable memory was designed for use in calculator but also used traffic light controller, Blood analyzers … 14
- 15. Intel microprocessors … 8-bits processors Intel 8008 first 8-bit microprocessor 200KHz clock speed and 3,500 transistors, had 6 , 8-bit registers 8-bit data bus can address up to 16KB Intel 8085 was popular as an embedded controller ran at 5MHZ and contained 6500 transistors 15
- 16. Intel microprocessors … 16-bits processors Intel 8086 1978,16-bit: all registers, internal and external buses Used 20-bit addressing Can address 1 million bytes of internal memory 29,000 transistors, 5MHz initially Intel 8088 was identical to the 8086 with the exception of its 8-bit internal bus The IBM 5150, the first IBM PC, came with the 8088 16
- 17. Intel microprocessors … 16-bits processors Intel 80286 can operate on real and protected mode 134,000 transistors, 6M-8MHz initially can address up to 16 million bytes of internal memory was popular in IBM-PC AT and AT PC clones 17
- 18. Intel microprocessors … 32-bits processors Intel 80386 the first 32-bit microprocessor 32 bit registers & data bus can operate on protected mode and supports virtual mode 275,000 transistors, 12MHz initially, later 33MHz Intel continued to manufacture the 80386 family until September of 2007 Intel single-source production of 386 to AMD Later changed in 1991 by AMD as AM386 18
- 19. Intel microprocessors … 32-bits processors Intel 80486 32 bit registers and data bus has a high speed cache memory, 8KB SRAM cache was launched with 25 to 50 MHz, included 1.2 million transistors 19
- 20. Intel microprocessors … 32-bits processors Pentium (Pentium I) 32 bit registers, 64 bit data bus Has a high speed cache memory It can execute more than one instruction per clock cycle Pentium II and III Have a dual independent bus that provides separate path to the system cache and memory On-die L2 cache 20
- 21. Intel microprocessors … 64-bits processors New instruction set, not at all related to x86. Itanium Released May 29, 2001 733 MHz to 800 MHz 2MB cache Itanium 2 Released July 2002 900 MHz – 1.6 GHz 21
- 22. Intel microprocessors … 64-bits processors Intel core 2 x86-64 microprocessor Two cores on one die Number of transistors: 291 million 64 KB of L1 cache per core 1.86-3.00 GHz Intel core i series Intel core i3, i5, i7 22
- 23. Reading Assignment 1 24 Micro-processor vs micro-controller Multi-core processor vs multi-processor CPU vs GPU Multi-threading and hyper-threading Overclocking
- 24. What is an x86 architecture? x86 is a family of backward compatible instruction set architectures based on the Intel 8086 CPU the term "x86" came into being because the names of several successors to Intel's 8086 processor end in "86", including the 80186, 80286, 80386 and 80486 processors all newer processors using Intel's x86 instruction set are still referred to as x86, i386, or i686 compatible (which means they all use extensions of the original 8086 instruction set) 25
- 25. Intel 8086 1978, first x86 family microprocessor 16-bit: all registers, internal and external buses can address 1 million bytes of internal memory used 20-bit addressing to date backward compatibility has been maintained 26
- 26. 8086 Microprocessor Architecture The Basic Architecture of the Intel 8086 The processor is partitioned into two logical units Execution Unit (EU) Bus Interface Unit(BIU) Why partition is needed? Because the processor runs considerably faster than memory 27
- 28. Execution Unit takes care of the processing including arithmetic and logic operations its role is to execute instructions Contains ALU, Control Unit and Registers 29
- 29. Bus Interface Unit (BIU) Its role is to deliver instructions and data to the EU Function to manage the bus control unit, segment registers and instruction queue to provide access to instructions from memory and place them in an instruction queue, which varies in size depending on the processor This feature enables the BIU to look ahead and prefetch instructions so that there is always a queue of instructions ready to execute 30
- 30. Internal Memory of 8086 Memory consists of cells organized in 8-bit groups Bytes in memory are numbered consecutively, beginning with 00 8086 was able to address 1MB of memory has 20bits wide memory address 31
- 31. Intel 8086- Memory RAM From the 1MB of memory, the first 640K is base RAM is used for temporary program storage ROM The 8086 Basic Input/Output System (BIOS) begins at address 768K and handles I/O devices, such as a hard disk controller ROM beginning at 960K controls the computer’s basic functions Power-On Self-Test, dot patterns for graphics, and the disk self-loader 32
- 32. Memory Segments Memory segmentation is the division of computer's primary memory into segments or sections Segments are special areas defined in a program for containing the code, the data, and what is known as the stack A segment begins on a paragraph boundary, that is, at a location evenly divisible by 16, or hex 10. 33
- 33. Memory Segments … In real mode, the three main segments are code, data, and stack Code Segment: Contains the machine instructions to be executed The first executable instruction is at the start of this segment, and the operating system links to that location to begin program execution Data Segment: Contains a program’s defined data, constants, and work areas Stack Segment: Contains any data and addresses that the program needs to save temporarily for use on subroutines A program may contain one or more segments, which may vary in size, and can be defined in any sequence 34
- 34. 8086/8088 Registers The registers are categorized into two sets: Data registers are for calculations Address registers used to store memory addresses that point to locations in memory where data will be retrieved or stored 35
- 35. 8086/8088 Data Registers aka general purpose registers, these are AX - Accumulator register BX - Base register CX - Counter register DX - Data register each are 16-bit long and can also be accessed as two 8-bit registers AX AH & AL BX BH & BL CX CH & CL DX DH & DL The 80386 introduced an extended 32-bit general purpose registers named EAX, EBX, ECX and EDX 36
- 36. 8086/8088 Data Registers AX register is used for operations involving input/output and arithmetic BX register given the name base register because it is the only general purpose register that can be used as an index in indirect addressing can also be used for computations CX register usually used to control the number of times a loop is repeated or a value to shift bits left or right in bit shifting operations can also be used for computations DX register is used for operations involving input/output and most arithmetic 37
- 37. 8086/8088 Address Registers Segment registers: used to store starting address of memory segments Code Segment register Data Segment register Stack Segment register Extra Segment register Index registers: used for indexed addressing and string operations Source Index register Destination Index register Pointer registers: used to store offset address within memory segments Instruction Pointer register Stack Pointer register Base Pointer register All the above address registers are 16-bit long in 8086/8088 38
- 38. 8086/8088 Segment Registers CS register: used to hold starting address of program’s code segment DS register: used to hold starting address of program’s data segment SS register: used to hold starting address of program’s stack segment ES register: used to hold starting address of programmers defined extra data segment FS and GS registers: additional extra segment registers introduced by the 80386 39
- 39. 8086/8088 Pointer Registers IP (Instruction Pointer) register used to locate a specific location within the code segment used to hold offset address of the next instruction to be executed SP (Stack Pointer) register used to hold offset address of the top of the stack segment points to the current word being processed in the stack BP (Base Pointer) register used to point to a specific location in the stack 40
- 40. 8086/8088 Index Registers SI (Source Index) & DI (Destination Index) registers are used to locate a specific location within the data segment both are used in string handling operations. In this context, SI is associated with the DS register while DI is associated with the ES register 41
- 41. Flags Register Is the status register in Intel x86 microprocessors that shows the current state of the processor In 8086 flags register is 16 bits wide, among which 9 are active They are modified automatically by the processor after instruction execution, which allows to determine the type of the result and also conditions to transfer control to other parts of the program 42
- 42. Flags Register … The flags bits has two groups Status flags: reflect the result of an operation executed by the processor SF, ZF, AF, CF, PF & OF Control flags: enable or disable certain operations of the processor Trap flag (TF) Interrupt flag (IF) Direction flag (DF) 43
- 43. Flags Register: Status Flags SF (Sign): Indicates the resulting sign of an arithmetic operation (0 = positive and 1 = negative) ZF (Zero): Indicates the result of an arithmetic or comparison operation (0 = nonzero and 1 = zero result) PF (Parity): indicates the number of 1-bits that result from an operation. (0=even parity and 1 = odd parity) AF (Auxiliary Carry): contains a carry out of bit 3 into bit 4 in an arithmetic operation OF (Overflow): indicates overflow of a high-order(leftmost) bit following in a signed arithmetic operation CF(Carry): contains carries from a high-order bit following an unsigned arithmetic operation; also contains the contents of the last bit of a shift or rotate operation 44
- 44. Flags Register: control flags The Interrupt Flag Indicates that external interrupts, such as keyboard entry, are to be processed or ignored Clearing IF (IF=0) disables interrupts The Direction Flag Determines left or right direction for moving or comparing string (character) data If DF=1, the string instruction will automatically decrement the pointer The Trap Flag Permits operation of the processor in single-step mode Setting TF (TF=1) puts the processor into single step mode for debugging, where the processor automatically generates an internal interrupt after each instruction, allowing a program to be inspected as it executes instruction by instruction 45