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CS/COE0447

Computer Organization & Assembly Language

Course Introand

CH 1.1-1.3

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Course Information

• Welcome to CS/COE0447!• Professor

– Dr. Jan Wiebe

• Teaching Assistant– Jose Baiocchi

• Course web page, including syllabus, lectures notes, assignments, labs, schedule, …– http://www.cs.pitt.edu/~wiebe/courses/CS447/Sp10

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Computer Systems

• “Desktop computers”– E.g. PCs, MACs, …– Includes Notebooks

• “Servers”– Web servers– File and compute servers– Supercomputers

• “Embedded computers”– Usually NOT directly observable– Very wide range of applications

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Desktop Computers

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Servers

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Embedded Computers

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Computer Organization

We study this part in this course!

Study this part in CS1541!

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In CS/COE 447• We will study

– Computer architecture• MIPS architecture

– Concepts of assembler, linker, compiler– Computer arithmetic

• Signed and unsigned binary numbers• Floating point format• Operations (add/div/…)

– Logic design– Basic processor performance analysis– Processor organization

• Datapath• Control

• We will do– Assembly language programming (in MIPS)

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Computer Architecture?

• Computer systems– Underlying hardware– Software running on it

• Computer architecture– The hardware/software interface seen by the user – Instruction set architecture (ISA)

• Processor microarchitecture– Implementation of a given architecture– May or may not be visible to the user

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Transistors

Layered Approach in Computer Design

Computer Architecture orInstruction Set Architecture

Logic gates

Microarchitecture

Architecture

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Machine Code Example

swap:muli $t0, $a0, 4add $t0, $a1, $t0lw $t1, 0($t0)lw $t2, 4($t0)sw $t2, 0($t0)sw $t1, 4($t0)jr $ra

void swap(int v[], int k){

int temp;temp = v[k];v[k] = v[k+1];v[k+1] = temp;

}

00000000101000010…00000000000110000…10001100011000100…10001100111100100…10101100111100100…10101100011000100…00000011111000000…

com

piler

assemble

r

Chapter 1 — Computer Abstractions and Technology — 12

Levels of Program Code• High-level language

– Level of abstraction closer to problem domain

– Provides for productivity and portability

• Assembly language– Textual representation of

instructions

• Hardware representation– Binary digits (bits)– Encoded instructions and

data

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Components of ISA

• In most cases, a “programmer’s reference manual” (PRM) will disclose the ISA of a processor

• To understand an ISA, find in PRM– Data types the processor supports– Supported instructions and their definitions– Registers (general-purpose & special

purpose)– Processor modes– Exception mechanism

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Inside a PC

• Integrated Circuits (ICs)– CPU (Central Processing Unit), companion chipset, memory,

peripheral I/O chip (e.g., USB, IDE, IEEE1394, …)• Printed Circuit (PC) boards (next slide)

– Substrate for ICs and interconnection– Distribution of clock, power supply– Heat dissipation

• Hard disk, CD-RW DVD-RW, (floppy disk)• Power supply• Chassis

– Holds boards, power supply, and provides physical interface for user and other systems

• Connectors and cables

15Closeup photo of one side of a motherboard PCB, showing conductive traces and solder points for through-hole components on the opposite side.

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Technology Trend (Processor Complexity)

2x transistors/chip every 1.5 years!

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Moore’s Law• The term Moore's Law has been coined by Carver Mead around

1970.[4] Moore's original statement can be found in his publication "Cramming more components onto integrated circuits", Electronics Magazine 19 April 1965:

• “The complexity for minimum component costs has increased at a rate of roughly a factor of two per year ... Certainly over the short term this rate can be expected to continue, if not to increase. Over the longer term, the rate of increase is a bit more uncertain, although there is no reason to believe it will not remain nearly constant for at least 10 years. That means by 1975, the number of components per integrated circuit for minimum cost will be 65,000. I believe that such a large circuit can be built on a single wafer.[1]

• Astounding that it has held for so long!!!

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Memory Capacity Trend (DRAM)

1.4x/year or 2x every 2 years8000x since 1980!

size

Year

Bit

s

1000

10000

100000

1000000

10000000

100000000

1000000000

1970 1975 1980 1985 1990 1995 2000

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Main memory

• PC/servers use “DRAM” (Dynamic RAM)– SDRAM– DDR SDRAM– RDRAM (RAMBUS DRAM)

A typical SDRAM “module”

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Storage

• Secondary storage

• Non-volatile

• Stores programs, user-saved data, etc.

• In PC/server domain, magnetic disk (hard-disk) is usually used

• In embedded computers, “flash” memory or “ROM” is usually employed

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Storage, cont’d

5.25-inch floppy disk1.2MB

3.5-inch floppy disk1.44MB

USB Flash card256MB

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Storage, cont’d

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Computer Networks

• Local Area Network (LAN)– Within limited distance (e.g., in a building)– Mostly based on Ethernet– 10Mbps, 100Mbps, 1Gbps, 10Gbps, …

• Wide Area Network– Connecting networks far apart

• Proliferation of wireless LAN (IEEE802.11)– 1 ~ 100Mbps