Data Manipulation. Chih-Wei Tang ( 唐之瑋 ) Department of Communication Engineering National Central University JhongLi, Taiwan

Transcription

1 Data Manipulation Chih-Wei Tang ( 唐之瑋 ) Department of Communication Engineering National Central University JhongLi, Taiwan

2 Outline Computer Architecture Machine Language Program Execution Arithmetic/Logic Instructions Communicating with Other Devices C.E., NCU, Taiwan 2

3 Computer Architecture Central Processing Unit (CPU) or processor arithmetic/logic Unit (ALU): perform data manipulation control Unit: coordinate the machine s activities registers: temporary storage of information general purpose registers a temporary holding places for data being manipulated by the CPU Inputs to the ALU circuitry Results produced by ALU circuitry special-purpose registers cache Memory Bus Motherboard C.E., NCU, Taiwan 3

4 Cache Memory Cache memory keep a copy of that portion of main memory that is of current interest register cache memory CPU can execute more rapidly update main memory if data change Main memory: data that will be needed in the near future Mass storage: data that will likely not be needed in the near future C.E., NCU, Taiwan 4

5 CPU & Main Memory C.E., NCU, Taiwan 5

6 Adding Values Stored in Memory C.E., NCU, Taiwan 6

7 Outline Computer Architecture Machine Language Program Execution Arithmetic/Logic Instructions Communicating with Other Devices C.E., NCU, Taiwan 7

8 Machine Language Machine instruction = an instruction coded as a bit pattern directly recognizable by the CPU Machine language = the set of all instructions recognized by a machine Reduced Instruction Set Computing (RISC) CPU executes minimal set of machine instructions few, simple, efficient, and fast instructions example: PowerPC from Apple/IBM/Motorola Complex Instruction Set Computing (CISC) CPU executes a large number of complex instructions, even though man of them are technically redundant the more complex CPU is easier to program example: Pentium from Intel C.E., NCU, Taiwan 8

9 Machine Instruction Types Data Transfer Copy data between CPU and main memory LOAD : fill a general-purpose register with the contents of a memory cell STORE : transfer the contents of a register to a memory cell I/O instructions : communicating with devices outside the CPU-main memory context (printers, keyboards, monitors, disk drives, etc.) C.E., NCU, Taiwan 9

10 Machine Instruction Types Arithmetic/Logic Use existing data values to compute a new data value Tell the control unit to request an activity within the arithmetic/logic unit AND, OR, and XOR SHIFT : the bits that fall off the end of the register are discarded ROTATE : fill the holes left at the other end C.E., NCU, Taiwan 10

11 Machine Instruction Types Control Direct the execution of the program rather than the manipulation of data JUMP unconditional jumps conditional jumps Dividing Values Stored in Memory C.E., NCU, Taiwan 11

12 A Machine Instruction Op-code: specifies which machine operation to execute one per instruction Operand: more detailed information about this operation number of operands varies depending on op-code C.E., NCU, Taiwan 12

13 Decoding The Instruction 35A7 C.E., NCU, Taiwan 13

14 Outline Computer Architecture Machine Language Program Execution Arithmetic/Logic Instructions Communicating with Other Devices C.E., NCU, Taiwan 14

15 Program Execution Controlled by two special-purpose registers within CPU program counter : address of next instruction instruction register : current instruction Machine cycle: 3 steps performed by control unit fetch decode execute C.E., NCU, Taiwan 15

16 A Machine Cycle C.E., NCU, Taiwan 16

17 Special Case Decoding the Instruction B258 C.E., NCU, Taiwan 17

18 Stored Program Concept A program is just a special type of data! a program can be encoded and stored in main memory the control unit extracts the program from memory, decode the instructions, and execute them The machine alone don t know what is data and what is program The computer just executes according to the program counter C.E., NCU, Taiwan 18

19 The Program Stored in Main Memory Ready for Execution C.E., NCU, Taiwan 19

20 Performing the Fetch Step of the Machine Cycle (1/2) C.E., NCU, Taiwan 20

21 Performing the Fetch Step of the Machine Cycle (2/2) C.E., NCU, Taiwan 21

22 Outline Computer Architecture Machine Language Program Execution Arithmetic/Logic Instructions Communicating with Other Devices C.E., NCU, Taiwan 22

23 Arithmetic/Logic Operations Logic: AND, OR, XOR Rotate and Shift circular shift logical shift : discard the bit that falls off the edge and always fill the hole with a 0 arithmetic shift : leave the sign bit unchanged Arithmetic: add, subtract, multiply, divide separate instructions for different types of data C.E., NCU, Taiwan 23

24 Outline Computer Architecture Machine Language Program Execution Arithmetic/Logic Instructions Communicating with Other Devices C.E., NCU, Taiwan 24

25 Controllers Attached to a Machine s Bus C.E., NCU, Taiwan 25

26 Controller Intermediary device : it handles communication between the computer and a device Physical form of a circuit board : it plugs into a slot on the computer s motherboard Format conversion : between a computer and a particular type of peripheral device Port = set of addresses assigned to a controller memory-mapped I/O : computer s I/O devices appear to be in various memory locations buses contain a signal : indicates whether the message is for a controller or memory C.E., NCU, Taiwan 26

27 A Conceptual Representation of Memory-Mapped I/O C.E., NCU, Taiwan 27

28 Communicating with Other Devices Direct memory access (DMA) a controller accesses main memory over the bus CPU is not using the bus CPU continues with other tasks while the controller performs read/write Von Neumann bottleneck: the CPU and the controllers compete for bus access von Neumann architecture: a computer design model that uses a single storage structure to hold both instructions and data coordination of these activities is a major design issue Handshaking 2-way dialogue the computer and the peripheral device exchange device s status and coordinate their activities C.E., NCU, Taiwan 28

29 Data Communication Rates Measurement units bps = bits per second Kbps = kilo-bps, or 1,000 bps Mbps = mega-bps, or 1,000,000 bps Gbps = giga-bps, or 1,000,000,000 bps Bandwidth = maximum available rate depends on the type of communication path and the technology used in its implementation C.E., NCU, Taiwan 29

30 Data Communication Path Types Parallel communication several lines transfer different bits simultaneously rapid complex communication path example: CPU peripheral devices (e.g., printers) rates: > Mbps Serial communication one line transfers one bit at a time slower communication between different computers example : telephone line modem : bit patterns (source) audible tones bit patterns (destination) (D/A A/D) C.E., NCU, Taiwan 30