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Location of the operand of an instruction may be obtained:
• Immediate: e.g. 200 (hex!)
Operand contained in 2nd
part of the instruction
• Register: e.g. BX
Operand is contained in one of the general registers
• Indirect: e.g. [200]
Operand’s address is contained in the 2nd
part of the instr.
• Register indirect: e.g. [BX]
Operand’s address is contained in one of the general
pointers or pointer/index registers
• Indexed: e.g. [BX+1]
Operand’s address is formed by adding displacement
contained in 2nd
part of the instr. to the contents of one of
the index registers
Addressing modes](https://image.slidesharecdn.com/computerlecture2-241024152208-c7f68aa9/85/computer_lecture2-pdf-what-is-computer-and-microprocessor-22-320.jpg)
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Addr. ML AL Meaning
Assembler example
100 BB 00 02 MOV BX,200 BX 200h (load addr.)
103 8A 2F MOV CH,[BX] CH value at loc 200h
105 8A 4F 01 MOV CL,[BX+1] CL value at loc 201h
108 88 0F MOV [BX],CL loc 200h CL
10A 88 6F 01 MOV [BX+1],CH loc 201h CH
10D CD 20 INT 20 software interrupt (exit
Location Value before Value after
200 A1 B2
201 B2 A1
202 ? ?
The program swaps values in locations 200 and 201
opcode lo hi](https://image.slidesharecdn.com/computerlecture2-241024152208-c7f68aa9/85/computer_lecture2-pdf-what-is-computer-and-microprocessor-23-320.jpg)
computer_lecture2.pdf what is computer and microprocessor
- 1. 1 Computers and Microprocessors Lecture 35 PHYS3360/AEP3630
- 2. 2 Contents • Input/output standards • Microprocessor evolution • Computer languages & operating systems • Information encryption/decryption
- 3. 3 • USB (universal serial bus) – intelligent high-speed connection to devices – up to 480 Mbit/s (USB 2.0 Hi-Speed) – USB hub connects multiple devices – enumeration: computer queries devices – supports hot swapping, hot plugging • Parallel – short cable, Enhanced PP up to 2 Mbit/s – common for printers, simpler devices – bidirectional, parallel data transfer (IEEE 1284) – Intel 8255 controller chip Input/Output Ports
- 4. 4 • Serial – one bit at a time – RS-232 (recommended standard 232) serial port – used with long cables (not longer than ~15 m OK) – low speeds (up to 115 kbit/s) – still widely used to interface instruments – additional standards available: • E.g. RS-422/485 differential signals for better noise immunity, can support speeds in access of 10 Mbit/s (becomes cable- length dependent) Input/Output Ports (2)
- 5. 5 • IEEE-488 (GPIB) – Has been around for 30 years, many instruments are equipped with it – Allows daisy-chaining up to 15 devices – Updated versions have speeds up to 10Mbit/s Input/Output Ports (3)
- 6. 6 • Generally characterized by the “word” size (registers and data bus) – 8-bit, 16-bit, 32-bit, 64-bit – addressable memory related to the word size • Intel 8080 (1974) – 8-bit, first truly usable m-processor (40 DIP) – seven 8-bit registers (six of which can be combined as three 16-bit registers) – 6K transistors, 2MHz clock – Other notable 8-bit processors include Zilog Z80 (1976) (used in Osborne 1, first portable m-computer) and Motorola 6800/6809 (1978) – Small cost, compact packaging allowed home computer revolution Microprocessor Evolution
- 7. 7 • Intel 8080 later variants – 64K addressable RAM (16-bit bus address) – 8-bit registers – CP/M (control program for m-computers) OS – 5,6,8,10 MHz – 29K transistors • Intel 8086/8088 (1978) – 16-bit processor, IBM-PC used 8088 – 1 MB addressable RAM (20-bit addresses) – 16-bit registers – 16-bit data bus (8-bit for 8088) – separate floating-point unit (8087) – used in low-cost microcontrollers now Early Intel Processors
- 8. 8 • Western Design Center (WDC 65816) – used in Apple II and Super Nintendo – fully CMOS, low power consumption (300 mA at 1MHz, operating voltage as low as 1.8V) – Wait-for-Interrupt and Stop-the-Clock instructions further reduce power consumption – one of the most popular (made in huge numbers) – Still sold today (original 1984), used as a controller – 24-bit address bus (16MB of memory space) • Texas Instrument TM9900, National Semiconductor IMP-16, etc. Other 16-bit processors
- 9. 9 • Intel 80286 (1982) – Still largely a 16-bit processor – 16 MB addressable RAM – Protected memory – several times faster than 8086 – introduced IDE bus architecture – 80287 floating point unit – Up to 20MHz – 134K transistors IBM-AT
- 10. 10 • Motorola 680x0 series – 32-bit registers – 68010 (1982) adds virtual memory support – Other successors 68020/68030/68040/68060 – Popular with UNIX operating systems in late 1980’s/early 1990’s – Faded from computer desktop market, but had a strong standing in embedded / controller equipment (still used) • “Microprocessor wars” – leads to elimination of some / survival of the fittest. In aftermath, the PC market to be largely dominated by IA- 32; however, much more diversity exists for the controllers 32-bit processors
- 11. 11 • Intel386 (1985) – 4 GB addressable RAM – 32-bit registers – paging (virtual memory) – Up to 33MHz • Intel486 (1989) – instruction pipelining – Integrated FPU – 8K cache • Pentium (1993) – Superscalar (two parallel pipelines) – Intel declines to license Pentium to others, AMD and Cyrix start their own designs IA-32
- 12. 12 • Pentium Pro (1995) – advanced optimization techniques in m-code – More pipeline stages – On-board L2 cache • Pentium II (1997) – MMX (multimedia) instruction set – Up to 450MHz • Pentium III (1999) – SIMD (streaming extensions) instructions (SSE) – Up to 1+GHz • Pentium 4 (2000) – NetBurst micro-architecture, tuned for multimedia – 3.8+GHz • Pentium D (Dual core) • … Intel Pentium Family
- 13. 13 • 2003 data (from Wikipedia) – $44 billion dealt in business on microprocessors – Personal computers account for 50% of cost but only 0.2% of all CPU’s sold – 55% of all CPU’s sold are 8-bit controllers (many billions sold overall) – Less than 10% of all CPU’s are 32-bit or more – Of all 32-bit processors sold, only 2% are used in personal computers (laptops/desktops) – “Taken as a whole, the average price for microprocessor, microcontroller, or DSP is just over $6” – Read more at http://www.embedded.com/shared/printableArticle.jhtml?articleID=9900861 Some interesting statistics
- 14. 14 Programming • Interpreted High Level Language • Compiled High Level Language • Assembly Language • Machine Language
- 15. 15 Programming (2) • Machine Language – binary instructions (op codes) actually read and interpreted by the CPU Ex: 1000 1011 0000 0101 ‘move value from memory to AX register’ on 386 – different for each CPU type • Assembly Language – CPU instructions represented by mnemonics Ex: MOV AX, M same as above – each AL instruction converts to one ML instruction by assembler program – Efficient fast execution, inconvenient to program in – Allows access to instructions not available with higher
- 16. 16 Programming (3) • High Level Language, e.g. C/C++ – easier to use – it’s compiler’s job to translates (one) HLL instruction into (many) ML instructions – portable: can compile the same source (HLL instructions) on different OS platforms – slower and more restricted • Interpreted Languages, e.g. JAVA, scripting – on-the-fly translation of high level language – slowest of the above, but often a good place to start with a new project
- 17. 17 m-processor: registers CS SS DS ES EIP EFLAGS 16-bit Segment Registers EAX EBX ECX EDX 32-bit General-Purpose Registers FS GS EBP ESP ESI EDI Storage locations inside the CPU, optimized for speed. Control registers
- 18. 18 m-processor: registers (2) • General Purpose Registers: used to contain arithmetic and logical operands used by ALU • Segment Registers: indicate segments of memory currently in use. – CS: (code segment) memory segment where instructions/program are located – DS: (data segment) … – SS: (stack segment) … – ES: (extra segment) … • Pointer & Index Registers: – BP: base pointer – SP: stack pointer – SI: source index – DI: destination index complete address = segment + pointer/index
- 19. 19 • Control Registers: – IP/IR: instruction pointer held in instruction register (memory address of next instruction to be executed) – FLAGS: status and control flags; used to indicate processor status m-processor: registers (3) o i s z p c 11 10 9 8 7 6 5 4 3 2 1 0 c = 1: if operand produced carry p = 1: if operand has parity of 1 z = 1: if result = 0 s = 1: if result < 0 i = 1: m-processor will respond to interrupts o = 1: if result produced overflow
- 20. 20 • Fetch the next instruction (address is held in instruction pointer / register); instruction pointer is incremented to the next value or branched, conditional statements may throw it elsewhere • Decode: what do 1’s and 0’s mean? • Execute: the instruction m-processor instruction cycle
- 21. 21 • Data Transfer: MOV d,s move (s)ource to (d)estination • Arithmetic: ADD d,s add s to d and store it in d INC d increment contents of d by 1 • Logical and Shifts: AND d,s bitwise AND of s with d, store in d SHL d shift d left one bit • Control Transfer: JMP loc jump to memory location loc JE loc jump to loc if result of last operation = 0 • I/O: OUT d,s output to the I/O space (address d) some basic assembler instructions
- 22. 22 Location of the operand of an instruction may be obtained: • Immediate: e.g. 200 (hex!) Operand contained in 2nd part of the instruction • Register: e.g. BX Operand is contained in one of the general registers • Indirect: e.g. [200] Operand’s address is contained in the 2nd part of the instr. • Register indirect: e.g. [BX] Operand’s address is contained in one of the general pointers or pointer/index registers • Indexed: e.g. [BX+1] Operand’s address is formed by adding displacement contained in 2nd part of the instr. to the contents of one of the index registers Addressing modes
- 23. 23 Addr. ML AL Meaning Assembler example 100 BB 00 02 MOV BX,200 BX 200h (load addr.) 103 8A 2F MOV CH,[BX] CH value at loc 200h 105 8A 4F 01 MOV CL,[BX+1] CL value at loc 201h 108 88 0F MOV [BX],CL loc 200h CL 10A 88 6F 01 MOV [BX+1],CH loc 201h CH 10D CD 20 INT 20 software interrupt (exit Location Value before Value after 200 A1 B2 201 B2 A1 202 ? ? The program swaps values in locations 200 and 201 opcode lo hi
- 24. 24 I/O devices usually have their own registers which are assigned or mapped to addresses in memory I/O is achieved by m-processor reading from / writing to the corresponding memory addresses Ex: I/O user port used in the lab this week has 8 registers at addresses 2A0H 2A7H. Used to control ADC, DAC and digital I/O functions of the port. Input/Outputs
- 25. 25 • Provides a level of abstraction and security for higher level applications; interrupts, memory handling, etc. • I/O are privileged operations, usually only OS can do I/O • A device driver is provided, which runs as part of the OS • User’s program then communicates to the device through the driver and OS Operating System
- 26. 26 • Most OS can run multiple programs at the same time. • Multiple threads of execution within the same program. • Scheduler utility assigns a given amount of CPU time to each running program. • Rapid switching of tasks gives illusion that all programs are running at once • The processor must support task switching • Scheduling policy, priority, etc. OS: multitasking
- 27. 27 Used for handling peripheral I/O asynchronously (orders of magnitude differences in time required for access, enable/disable, read/write, etc.) Device requiring services asserts Interrupt Request. When INTR asserted: • m-processor completes execution of current instruction • IP/IR & other registers pushed onto stack • IP/IR loaded with address of interrupt routine • interrupt routine executed to identify and service the device • when completed, IP & registers popped from stack, and program execution resumes Interrupts
- 28. 28 General purpose OS systems such as Linux, Windows, Mac OS do not guarantee ‘real-time’ execution of instructions i.e. they don’t necessarily have any operational deadlines from event to system response e.g. various interrupts, multitasking, etc. are usually handled with the illusion of smooth running for a casual user, but the behavior is not deterministic Multitasking operating systems are available that provide tools to ensure that certain deadlines from event to system response are met. Examples: VxWorks (Wind River) – used on Mars rovers RTLinux, RTEMS (o.source) Real Time Operating Systems
- 29. 29 Signal encryption using a sequence of pseudo-random numbers • Uses linear feedback shift registers (LFSR) to generate a sequence of pseudo-random numbers (deterministic sequence that looks random) • If LFSR has N bits, the max sequence will be 2N – 1 long, then repeats • E.g. 8-bit LFSR can produce 255 long sequence, 32-bit LFSR can produce 4,294,967,295 pseudo-random sequence • XOR gates are used to tap certain outputs into the serial input (see the table in the Supplement) LTspice experiment 11.1
- 30. 30 Pseudo-random number generator • 8-bit pseudo-random generator • Output random number is (Q7Q6Q5Q4Q3Q2Q1Q0)2 • At least one Qi bit must be non-zero initially for non-trivial (other than always 0’s) pattern • The initial state of Qi bits is known as seed, which uniquely defines the sequence of pseudo-random numbers
- 31. 31 Encrypting/decrypting • To encrypt scramble the stream of data bits with pseudo-random sequence: ENi = Ai PRi • How to decrypt? Ai = ENi PRi • Need the same unique sequence of pseudo-random numbers used for encryption (seed becomes encryption/decryption password). Information bit encrypted bit P-random bit
- 32. 32 • Implement pseudo-random number generator • Decrypt an encrypted 8-bit data stream • Perform digital-to-analog conversion and plot a parametric curve (x(t), y(t)) to display the secret message • E.g. explain how RSA encryption/decryption works • RSA = Rivest, Shamir, Adleman • Public key cryptography LTspice experiment 11.1 Things to read/think about
- 33. 33 Arduino – 30$ computer (Teensy – 19$) QCO Microcontroller ATmega328 Operating Voltage 5V Input Voltage (recommended) 7-12V Input Voltage (limits) 6-20V Digital I/O Pins 14 (of which 6 provide PWM output) Analog Input Pins 6 DC Current per I/O Pin 40 mA DC Current for 3.3V Pin 50 mA Flash Memory 32 KB (ATmega328) of which 0.5 KB used by bootloader SRAM 2 KB (ATmega328) EEPROM 1 KB (ATmega328) Clock Frequency 16 MHz Arduino Uno specs www.arduino.cc
- 34. 34 Arduino Mega Arduino UNO Arduino Mini/Nano Lilypad Different Arduinos