Study Guide – Exam 1 – CSC 317
What to expect:
About 3-5 multiple-choice questions, 1-3 True/False questions and 3-5 longer
problems or essay questions.
Chapters 1, 2 and external sources
 Motivation for learning COA
 Optimize code
 Vocabulary/acronyms – Comparing systems, benchmarking
 Interfacing systems (hardware compatibility)
 Writing device drivers
 Writing compilers
 How floating point arithmetic works
 What is a computer?
A system that accepts data, processes the data according to some instruction, &
produces some results.
abstraction
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

I
P
O
Basic elements of a computer
1. Processor
2. System interconnection
3. Main memory
4. Input/output
Architecture vs. Organization
 Architecture
Those features “visible” to a programmer
 Instruction set
 # bits used for data representation
 Addressing modes
E.g. ADD A, B, C
- 3-operand instruction
ADD A, B
ADD A
- accumulator
 Organization
How features are implemented.
E.g.
o How multiply is implemented
o Control signals
o Interfaces
o Memory technology
Evolution of computers:
o ENIAC
 John Mauchly, John Eckert, University of Pennsylvania,
 first general purpose electronic digital computer,

purpose: develop range and trajectory tables for the Army’s
Ballistics Research Laboratory for WWII
 year built: started in 1943, finished in 1946
o Von Neumann machine
 Importance: stored program concept
 Stored program concept:
 Memory holds instructions & data
 No more rewiring
 Program can be altered by changing the memory content
 IAS architecture
 Princeton Institute of Advanced studies
 Completed 1952
 Same general structure and function as today’s computers
o A main memory, which stores both data &
instructions
o An arithmetic and logic unit (ALU) capable of
operating on binary data
o A control unit, which interprets the instructions in
memory and causes them to be executed
o Input and output (I/O) equipment operated by the
control unit
Memory
ALU
Program
Control
Unit
I/O
Data Processing Control
Unit
AC
MQ
ALU
I/O
MBR
memory
IBR
IR
MAR
Control
unit
PC
control
signals
Program Control Unit
o IBM 7094
 Data channel
 Independent I/O module with its own processor &
instruction set
 Multiplexer
 Precursor of the bus architecture
 It schedules access to main memory from CPU & data
channels
o Moore’s Law
 States that chip density doubles every 12 months
 Gordon Moore
o Important technology in each computer generation
0. devices before computers
 mechanical calculators
1. vacuum tubes
2. transistors
3. IC (Integrated Circuits)
4. microprocessor
 processor in a chip
5. RISC (reduced Instruction Set Computer)
6. Large capacity, low cost disc system & memory
 Faster microprocessors

Performance considerations:
o Mismatch interface between processor and main memory
o Solutions to solving the mismatch
 Make DRAM “wider” rather than “deeper”
 Increase the # of bits retrieved at one time
 Change DRAM interface to make it more efficient
 By including cache
 Reduce frequency of memory access
 Using complex cache structure
 Increase interconnection bandwidth
 Use higher speed buses
 Use hierarchal buses
 Performance measures:
o Benchmark programs
 Measure of execution performance based on average figures
o Equation about execution time
 Suppose you have a set of benchmark programs: Q
 It takes T seconds to execute them
 N: is number of instruction executed
 Parameter 1: average # of instructions per second: I
 Parameter 2: average # of cycles per instruction: C
 f: clock frequency in MHz
f 106
 C
I
N
N C
architecture
 T


6
6
hardware
f  10
f  10
C
Chapter 3
 CPU registers
 Instruction cycles
o Fetch
 PC holds address of the next instruction to be fetched
 Processor fetches next instruction pointed to by the PC
 Increments PC (unless told otherwise)
 Instruction is loaded into IR
 Processor decodes instruction in IR
o Execute
Processor executes one of the following actions
 CPU – MM data transfer
 CPU – I/O data transfer
 Data Processing
 Control
 Combination of above
o Interrupt
start
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


Fetch
Interrupt
Execute
What is an interrupt, and its advantage?
Mechanism by which other modules (e.g. I/O) may interrupt the normal
processing of the CPU.
Classes of interrupts
o Program: as a result of program execution
Example: division by zero
o Timer: generated by internal processor timer
used in preemptive, multitasking OS
o I/O: on I/O controller signal the CPU at the completion of some I/O task,
(or some error condition)
o Hardware failure:
e.g. memory parity error
Handling multiple interrupts
2 ways of handling
o Define priority
Allow a higher priority interrupt to interrupt a lower priority interrupt
Processor returns to previous interrupt after the hi priority has been
processed
o Disable interrupts
Physical implementation of interrupts
1
CPU
INTA
M1
Daisy chain
1
M2
0
Mn
INTN
INT2
CPU
interrupt
arbiter
INT1
M1
Mn
M2
INTA1
INTA2
INTAn
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Types of exchanges between different components of a computer
Buses
o Definition
 A bus is a communication pathway connecting 2 or more devices.
o Fundamental groups
 Data bus
 Address bus
 Control bus
o Single bus problem
 Propagation delay
more time to coordinate the bus
bandwidth shared
o Hierarchal buses
Bus types
o Traditional bus architecture
o High-performance architecture
Bus arbitration
Bus timing
PCI bus: (Peripheral Component Interconnect)
o Principal features
 High bandwidth
 Processor-independent
 Released by Intel in 1990
 Current standard
 64 data lines
 528 Mbytes/sec
 Address and data multiplexed lines
 49 mandatory lines
o Bus transfer operation
 Diagram pg 86
Chapter 9
 Integer representation
o Sign magnitude

Left-most bit indicates if #
 positive: 0
 negative: 1
o two’s compliment
 Negative
for a number A
takes the complement of 1
add 1
 Range: -2n-1 to (2n-1-1)
o Addition
o Subtraction
B register
A register
Complimenter
Adder
Result
o Multiplication (Booth’s algorithm)


o Division
Floating point representation
o Number representation and normalization
o IEEE 754 standard
o Addition
o Subtraction
o Multiplication
o Division
Precision considerations:
o Guard bits and rounding
1. 4 types
2. ??
3. ??
4. ??
Chapter 10
 Elements of an instruction
1. opcode
2. source operands
3. result operands
4. next instruction
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

Number of addresses
Types of operands
Types of operations
o Procedure call instructions
o Stack frame
o Frame pointer