Transcript Data manipulation, Part one 2010/2011

Data manipulation, Part one
Introduction to computer, 2nd semester, 2010/2011
Mr.Nael Aburas [email protected]
Faculty of Information Technology
Islamic University of Gaza
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overview
In this chapter we will study how
computer manipulates the data.
 Moving data from one location to another
 Performing operations such as: arithmetic
calculations, text editing, and so on.

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Computer architecture
 The
circuitry in the computer that
control the manipulation of data is called
the CPU.
 CPUs were large units comprised of
several racks of electronic circuitry.
 Today's, CPUs are packaged as small flat
squares whose connecting pins plug into
a socket mounted in the main board.
 Due to their small size, these processors
are called microprocessor.
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CPU basics

Consists of three parts
◦ Arithmetic/Logic unit
 Performs operations on data (addition, subtraction)
◦ Control unit
 Coordinating the machine’s activities
◦ Registers
 Contain data storage cell that are used to
temporary storage within the CPU.
 (similar to main memory cells)
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CPU basics
 The
registers hold the inputs to the
arithmetic/logic unit and provide storage
space for results produced by that unit.
 The control unit transfer data from a
main memory into registers, inform the
arithmetic/logic unit which the register
hold the data, activates the appropriate
circuitry within the arithmetic/logic unit,
and tells the arithmetic/logic unit which
register should receive the result.
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Bus

For the purpose of transferring bit, a CPU and main
memory are connected by a collection of wires called
a bus.
 (wires connecting CPU and main memory)
Through this bus, the CPU read data from main
memory by supplying the address of the pertinent
memory cell along with an electronic signal telling the
memory that it is supposed to retrieve the data in the
indicated cell.
 CPU writes data in memory by providing the address
of the destination cell and the data to be stored
together with electronic signal telling the main
memory that it is supposed to store the data being
sent to it.

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Bus

CPU and main memory are connected via a bus
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Stored-program concept
 The
idea of storing a computer’s program
“instructions” in the main memory.
 Storage of instructions in computer
memory to enable it to perform a variety
of tasks in sequence
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Machine language
 Machine
language: The set (collection)
of all instructions recognized by a
machine (CPU)
 Machine instruction: An instruction
(or command) encoded as a bit pattern
recognizable by the CPU
 Compilers
and interpreters translate
from high-level language to machine
language
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Machine language

RISC (reduced instruction set computer)
 CPU should be designed to execute a minimal
set of machine instructions.
 (Few, simple, efficient, and fast instructions).
 In this architecture, such mahcine is efficent and
fast.

CISC (complex instruction set computer)
 Ability to excute a large number of complex
instructions.
 More complex cpu is easier to program because
single instruction can be used to accomplish a
task that would require a multi-instruction
sequence in a RISC design.
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Machine Instruction Types

Machine instruction can be categorized
into three grouping:
◦ Data transfer
◦ Arithmetic/logic
◦ control
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Data transfer
 Data
transfer group consists of
instructions that request the movement
of the data from one location to another.
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Data transfer

A special terms are used when referring
to the transfer of data between the CPU
and the main memory
◦ A request to fill a register with the contents
of a memory cells is referred to as a LOAD
instruction.
◦ A request to transfer the contents of a
register to a memory cell is called a STORE
instruction.
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Data transfer

I/O instructions: the instructions that
handle the input/output activities of the
machine
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Arithmetic/logic group
The instruction that tell the control unit
to request an activity within the
arithmetic/logic unit.
 The arithmetic/logic unit perform the
Boolean operations
 The instructions that allows the contents
of registers to be moved to the right or
the left within the register, such as SHIFT,
ROTATE.

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Control group
These instructions direct the execution of
the program.
 This group contains many of the
instructions in the machine such as the
family of JUMP instructions that used to
direct the CPU to execute an instruction
other than the next one in the list.

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An illustrative machine language


The machine instruction that will be described consists of two
parts:
Op-code
◦ Indicates which of the operations such as (STORE, SHIFT…etc) are
requested by the instruction.

Operand
◦ Provide more detailed information about the operation specified by the
op-code


The machine has 16 register and 256 main memory cells, each of
capacity eight bit.
For referencing purposes, the registers are labeled 0 through F, and
the main memory cells are addressed 00 through FF.
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An illustrative machine language
The machine language for our illustrative
machine is are shown in Appendix C.
 Each of these instructions is encoded using
total of 16 bit, represented by four
hexadecimal digits.
 As shown in appendix c, the instruction that
begin with op-code 3refer to a STORE
instruction, and which begn with A refers to
a ROTATE instruction.
 If the op-code is 3, then the next
hexadecimal digit of the instruction indicate
which register is to be stored.

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An illustrative machine language

Example: 35A7, translates to the
statement “ STORE the bit pattern found
in register 5 in the main memory cell
whose address is A7.
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Figure 2.6 Decoding the instruction 35A7
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Appendix C: A Simple Machine Language
Op-code
1
Operand
RXY
Description
LOAD the register R with the bit
pattern found in the memory cell
whose address is XY.
3
RXY
STORE the bit pattern found in
register R in the memory cell whose
address XY.
5
RST
ADD the bit pattern in register S
and T and leave the result in
register R. (2’s comp.)
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Adding values stored in memory
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An encoded version of the instructions in previous slide
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Exercise
The following are instructions written in the
machine language described in appendix C
rewrite them in English.
a)
b)
c)
d)
368A
BADE
803C
40F4
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Exercise

Here are some instructions in English. Translate
each of them into the machine language of
appendix C
a) LOAD register number 3 with the hexadecimal
value 56
b) ROTATE register number 5 three bits to the right
c) AND the contents of register A with the contents
of register 5 and leave the result in register 0
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