Evolution of microprocessors

A microprocessor is an electronic component that is used by a computer to do its work. It is a central processing unit on a single integrated circuit chip containing millions of very small components including transistors, resistors, and diodes that work together. Some microprocessors in the 20th century required several chips. Microprocessors help to do everything from controlling elevators to searching the Web. Everything a computer does is described by instructions of computer programs, and microprocessors carry out these instructions many millions of times a second. [1]

Microprocessors were invented in the 1970s for use in embedded systems. The majority are still used that way, in such things as mobile phones, cars, military weapons, and home appliances. Some microprocessors are microcontrollers, so small and inexpensive that they are used to control very simple products like flashlights and greeting cards that play music when you open them. A few especially powerful microprocessors are used in personal computers.

1. Evolution of Microprocessors

2. Intel 4004 First commercially available microprocessor produced in 1971. A 4 bit microprocessor with 45 instructions and a speed of 50K instructions per second (< ENIAC) Contained 2300 PMOS transistors. It was a 4 bit device used with some other devices to use it as a calculator.

3. Intel 8008 In 1972, Intel designed 8008 microprocessor working with 8 bit words and Motorola 6800. This required 20 or more additional devices to form a functional CPU.

4. Intel 8080 Designed in 1973, 8080 had a larger instruction set and required only 2 additional devices to form a functional CPU. NMOS transistors were used in this for faster operations.

5. Intel 8085 In 1977, Intel developed 8085 microprocessor with internal clock generator having higher frequency at reduced cost and integration. It was a single NMOS device implemented with 6200 transistors

6. Intel 8086 . This is the first actual processor designed in 1978 Object code programs created for these processors still can be executed on the latest members of Intel Architecture (IA) family. 8086 has 16 bit registers and 16 bit external data bus with 20-bit addressing giving 1MB address space.

7. Intel 8088 8088 was identical to 8086, except for a smaller external data bus of 8-bits. These processors introduced IA segmentation, but only in real mode. 16-bit registers could be used as pointers to address into segments of up to 64Kbytes in size

8. Intel 80186 Was never used

9. Intel 80286 In this processor, Protected Mode was introduced, in which segment register contents are selectors or pointers to descriptor tables. The descriptor provides 24 bit base addresses, allowing a maximum physical memory size of up to 16 Mbytes, support for virtual memory management on a segment swapping basis, and various protection mechanisms.

10. Intel 80386 This introduced 32 bit registers ( for operands) into the architecture, for both calculation & addressing The lower half of each 32 bit register retained the properties of one of the 16 bit registers of the earlier two generations, to provide complete upward compatibility. A new Virtual 8086 mode was provided to yield greater efficiency when executing programs created for the 8086 and 8088 processors on the new 32 bit machine. The 32 bit addressing was supported with an external 32 bit address bus giving a 4GBytes address space and also allowed each segment to be as large as 4 Gbytes

11. Intel 80486 8 KB unified level 1 cache for code and data was added to the CPU. In later versions of the 80486 the size of level 1 cache was increased to 16 KB. Intel 486 featured much faster bus transfers - 1 CPU cycle as opposed to two or more CPU cycles for the 80386 bus. Floating-point unit was integrated into 80486DX CPUs. This eliminated delay in communications between the CPU and FPU. Clock-doubling and clock-tripling technology was introduced in faster versions of Intel 80486 CPU. 80486SX2 and 80486DX2 were clock-doubled version, and 80486DX4 was a clock-tripled version. Power management features and System Management Mode (SMM) became a standard feature of the processor.

12. Intel Pentium Introduced in Mar 1993( First gen) and Mar 1994 . Maximum rated speeds : 60/66 MHz ( First gen) ;75/90/100/120/133/150/166/200 MHz ( Second gen.) CPU Clock multiplier : 1x(1st gen);1.5x -3x(2nd gen) Register size : 32 bit External Data bus : 64 bit Memory address bus : 32 bit Maximum memory : 4 GB

13. Intel Pentium II Bus speeds : 66 MHz; 100 MHz CPU clock multiplier: 3.5x, 4x, 4.5x, 5x CPU Speeds : 233 MHz, 266 MHz,300 MHz,333 MHz, 350 MHz, 400 MHz, 450 MHz Cache memory : 16K x 2( 32KB) L1,512KB – ½ speed L2 Internal registers: 32 bit External data bus: 64 bit system bus Memory address bus : 36 bit Addressable memory : 64 GB Virtual memory : 64 TB

14. Intel Pentium III The first Pentium III core, featured SSE instruction set, which allowed SSE-enabled applications to process up to four single-precision floating point numbers at once . Other Pentium 3 cores added other features, like 256 and 512 KB on-die L2 cache memory and smaller package size. During its lifetime, the core of Pentium III microprocessors was shrunk twice - from 0.25 micron to 0.18 micron, and then to 0.13 micron .

15. Intel Pentium IV Speeds range from 1.3 GHz – 3.8 GHz FSB speed : 400 MHz, 533 MHz, 800 MHZ, 1066 MHz Hyper pipelined/ hyper threading technology L2 cache can handle upto 4GB RAM Bus width is 64 bits

16. Microprocessor Generations First generation: 1971-78 Behind the power curve (16-bit, <50k transistors) Second Generation: 1979-85 Becoming “real” computers (32-bit , >50k transistors) Third Generation: 1985-89 Challenging the “establishment” (Reduced Instruction Set Computer/RISC, >100k transistors) Fourth Generation: 1990- Architectural and performance leadership (64-bit, > 1M transistors, Intel/AMD translate into RISC internally)

17. In the beginning (8-bit) Intel 4004 First general-purpose, single-chip microprocessor Shipped in 1971 8-bit architecture, 4-bit implementation 2,300 transistors Performance < 0.1 MIPS (Million Instructions Per Sec) 8008: 8-bit implementation in 1972 3,500 transistors First microprocessor-based computer ( Micral ) Targeted at laboratory instrumentation Mostly sold in Europe

18. 1st Generation (16-bit) Intel 8086 Introduced in 1978 Performance < 0.5 MIPS New 16-bit architecture “Assembly language” compatible with 8080 29,000 transistors Includes memory protection, support for Floating Point coprocessor In 1981, IBM introduces PC Based on 8088--8-bit bus version of 8086

19. 2nd Generation (32-bit) Motorola 68000 Major architectural step in microprocessors: First 32-bit architecture initial 16-bit implementation First flat 32-bit address Support for paging General-purpose register architecture Loosely based on PDP-11 minicomputer First implementation in 1979 68,000 transistors < 1 MIPS (Million Instructions Per Second) Used in Apple Mac Sun , Silicon Graphics, & Apollo workstations

20. 3 rd Generation: MIPS R2000 Several firsts: First (commercial) RISC microprocessor First microprocessor to provide integrated support for instruction & data cache First pipelined microprocessor (sustains 1 instruction/clock) Implemented in 1985 125,000 transistors 5-8 MIPS (Million Instructions per Second)

21. 4 th Generation (64 bit) MIPS R4000 First 64-bit architecture Integrated caches On-chip Support for off-chip, secondary cache Integrated floating point Implemented in 1991: Deep pipeline 1.4M transistors Initially 100MHz > 50 MIPS Intel translates 80x86/ Pentium X instructions into RISC internally