[CSE10100] Introduction to Computer

Engineering (컴퓨터공학 개론)

Chapter 6

Seungkyu Lee

Assistant Professor, Dept. of Computer Engineering

Kyung Hee University

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The von Neumann architecture !!!!

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Control Unit

Control unit

The organizing force in the computer

- Instruction register (IR)

Contains the instruction that is being executed

- Program counter (PC)

Contains the address of the next instruction to

be executed

Central Processing Unit (CPU)

ALU and the control unit called the Central Processing Unit, or CPU

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The Fetch-Execute Cycle

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Computer Operations

Computer

A programmable electronic device that can store, retrieve, and process data

Data and instructions to manipulate the data are logically the same and can be stored in the same place

What operations can a computer execute?

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Machine Language

Machine language

The language made up of binary coded instructions built into the hardware of a particular computer and used directly by the computer

Why would anyone choose to use machine language?

(Hint: they had no choice. Why?)

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Pep/8 Virtual Computer Virtual computer

A hypothetical machine designed to contain the important features of a real computer that we want to illustrate

Pep/8

A virtual computer designed by Stanley Warford that has 39 machine-language instructions

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Features in Pep/8 Pep/8 Registers/Status Bits Covered

– The program counter (PC) (contains the address of the next instruction to be executed)

– The instruction register (IR) (contains a copy of the instruction being executed)

– The accumulator (A register)

The memory unit is made up of 65,636 bytes of storage

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Architecture of Pep/8

Instruction Format

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Instruction Format Operation code

Specifies which instruction is to be carried out

Register specifier

Specifies which register is to be used (only use A in this chapter)

Addressing-mode specifier

Says how to interpret the operand part of the instruction

Instruction Format

Figure 6.3 Difference between immediate addressing mode and direct addressing mode

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Some Sample Instructions

Figure 6.4 Subset of Pep/8 instructions

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Sample Instructions

Operand Register

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Sample Instructions

Operand Register

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Sample Instructions

What do these instructions mean?

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Sample Instructions

What do these instructions mean?

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Sample Instructions

What do these instructions mean?

Written Algorithm of Hello

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In decimal?

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ASCII Character Set Mapping

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Hand Simulation 1

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Hand Simulation 1

Fetch!!!

Decode!!!

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Hand Simulation 1

Execute!!!

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Hand Simulation 2 Operand Register

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Hand Simulation 2

Fetch!!!

Decode!!! Operand Register

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Hand Simulation 2 Operand Register

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Hand Simulation 2 Operand Register

Execute!!!