Basic Concepts

Basic Concepts

COE 205

Computer Organization and Assembly Language

Computer Engineering Department

King Fahd University of Petroleum and Minerals

Basic Concepts COE 205 – Computer Organization and Assembly Language – KFUPMslide 2

Overview Welcome to COE 205 Assembly-, Machine-, and High-Level Languages Assembly Language Programming Tools Programmer’s View of a Computer System Basic Computer Organization Data Representation


Welcome to COE 205 Assembly language programming Basics of computer organization CPU design Software Tools

Microsoft Macro Assembler (MASM) version 6.15 Link Libraries provided by Author (Irvine32.lib and Irivine16.lib) Microsoft Windows debugger ConTEXT Editor


Textbook Kip Irvine: Assembly Language for Intel-Based Computers

4th edition (2003) 5th edition (2007)

Read the textbook! Key for learning and

obtaining a good grade

Online material http://

assembly.pc.ccse.kfupm.edu.sa/

http://assembly.pc.ccse.kfupm.edu.sa/





Course ObjectivesAfter successfully completing the course, students will be able to: Describe the basic components of a computer system, its instruction

set architecture and its basic fetch-execute cycle operation. Describe how data is represented in a computer and recognize

when overflow occurs. Recognize the basics of assembly language programming including

addressing modes. Analyze, design, implement, and test assembly language programs. Recognize, analyze, and design the basic components of a simple

CPU including datapath and control unit design alternatives. Recognize various instruction formats.


Course Learning Outcomes Ability to analyze, design, implement, and test assembly

language programs. Ability to use tools and skills in analyzing and debugging

assembly language programs. Ability to design the datapath and control unit of a

simple CPU. Ability to demonstrate self-learning capability. Ability to work in a team.


Required Background The student should already be able to program confidently in at

least one high-level programming language, such as Java or C. Prerequisite

COE 202: Fundamentals of computer engineering ICS 102: Introduction to computing

Only students with computer engineering major should be registered in this course.


Grading Policy Programming Assignments 15% Quizzes 10%

Exam I 15% (Sat. Nov. 3, 2007) Exam II 20% (Sat. Dec. 29, 2007) Laboratory 20% Final 20%

Attendance will be taken regularly. Excuses for officially authorized absences must be presented no later

than one week following resumption of class attendance. Late assignments will be accepted but you will be penalized 10% per

each late day. A student caught cheating in any of the assignments will get 0 out of

15%. No makeup will be made for missing Quizzes or Exams.


Course Topics Introduction and Information Representation: 6 lectures

Introduction to computer organization. Instruction Set Architecture. Computer Components. Fetch-Execute cycle. Signed number representation ranges. Overflow.

Assembly Language Concepts: 7 lecturesAssembly language format. Directives vs. instructions. Constants and variables. I/O. INT 21H. Addressing modes.

8086 Assembly Language Programming: 19 lecturesRegister set. Memory segmentation. MOV instructions. Arithmetic instructions and flags (ADD, ADC, SUB, SBB, INC, DEC, MUL, IMUL, DIV, IDIV). Compare, Jump and loop (CMP, JMP, Cond. jumps, LOOP). Logic, shift and rotate. Stack operations. Subprograms. Macros. I/O (IN, OUT). String instructions. Interrupts and interrupt processing, INT and IRET.


Course Topics CPU Design: 12

lecturesRegister transfer. Data-path design. 1-bus, 2-bus and 3-bus CPU organization. Fetch and execute phases of instruction processing. Performance consideration. Control steps. CPU-Memory interface circuit. Hardwired control unit design. Microprogramming. Horizontal and Vertical microprogramming. Microprogrammed control unit design.

Instruction Set Formats: 1 lectureFixed vs. variable instruction format. Examples of instruction formats.


Next … Welcome to COE 205 Assembly-, Machine-, and High-Level Languages Assembly Language Programming Tools Programmer’s View of a Computer System Basic Computer Organization Data Representation


Some Important Questions to Ask What is Assembly Language? Why Learn Assembly Language? What is Machine Language? How is Assembly related to Machine Language? What is an Assembler? How is Assembly related to High-Level Language? Is Assembly Language portable?


A Hierarchy of Languages


Assembly and Machine Language Machine language

Native to a processor: executed directly by hardware Instructions consist of binary code: 1s and 0s

Assembly language Slightly higher-level language Readability of instructions is better than machine language One-to-one correspondence with machine language instructions

Assemblers translate assembly to machine code Compilers translate high-level programs to machine code

Either directly, or Indirectly via an assembler


Compiler and Assembler


Instructions and Machine Language

Each command of a program is called an instruction (it instructs the computer what to do).

Computers only deal with binary data, hence the instructions must be in binary format (0s and 1s) .

The set of all instructions (in binary form) makes up the computer's machine language. This is also referred to as the instruction set.


Instruction Fields Machine language instructions usually are made up of

several fields. Each field specifies different information for the computer. The major two fields are:

Opcode field which stands for operation code and it specifies the particular operation that is to be performed. Each operation has its unique opcode.

Operands fields which specify where to get the source and destination operands for the operation specified by the opcode. The source/destination of operands can be a constant, the

memory or one of the general-purpose registers.


Assembly vs. Machine CodeInstruction Address Machine Code Assembly Instruction 0005 B8 0001 MOV AX, 1 0008 B8 0002 MOV AX, 2 000B B8 0003 MOV AX, 3 000E B8 0004 MOV AX, 4 0011 BB 0001 MOV BX, 1 0014 B9 0001 MOV CX, 1 0017 BA 0001 MOV DX, 1 001A 8B C3 MOV AX, BX 001C 8B C1 MOV AX, CX 001E 8B C2 MOV AX, DX 0020 83 C0 01 ADD AX, 1 0023 83 C0 02 ADD AX, 2 0026 03 C3 ADD AX, BX 0028 03 C1 ADD AX, CX 002A 03 06 0000 ADD AX, i 002E 83 E8 01 SUB AX, 1 0031 2B C3 SUB AX, BX 0033 05 1234 ADD AX, 1234h

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Translating LanguagesEnglish: D is assigned the sum of A times B plus 10.

High-Level Language: D = A * B + 10

Intel Assembly Language:mov eax, Amul Badd eax, 10mov D, eax

Intel Machine Language:A1 00404000F7 25 0040400483 C0 0AA3 00404008

A statement in a high-level language is translated typically into several machine-level instructions


Advantages of High-Level Languages

Program development is faster High-level statements: fewer instructions to code

Program maintenance is easier For the same above reasons

Programs are portable Contain few machine-dependent details

Can be used with little or no modifications on different machines

Compiler translates to the target machine language However, Assembly language programs are not portable


Why Learn Assembly Language? Two main reasons:

Accessibility to system hardware

Space and time efficiency

Accessibility to system hardware Assembly Language is useful for implementing system software

Also useful for small embedded system applications

Space and Time efficiency Understanding sources of program inefficiency

Tuning program performance

Writing compact code


Assembly vs. High-Level Languages

Some representative types of applications:


Assembler Software tools are needed for editing, assembling,

linking, and debugging assembly language programs

An assembler is a program that converts source-code programs written in assembly language into object files in machine language

Popular assemblers have emerged over the years for the Intel family of processors. These include … TASM (Turbo Assembler from Borland)

NASM (Netwide Assembler for both Windows and Linux), and

GNU assembler distributed by the free software foundation

You will use MASM (Macro Assembler from Microsoft)


Linker and Link Libraries You need a linker program to produce executable files

It combines your program's object file created by the assembler with other object files and link libraries, and produces a single executable program

LINK32.EXE is the linker program provided with the MASM distribution for linking 32-bit programs

We will also use a link library for input and output

Called Irvine32.lib developed by Kip Irvine

Works in Win32 console mode under MS-Windows


Assemble and Link ProcessSource

File

SourceFile

SourceFile

AssemblerObject

File

AssemblerObject

File

AssemblerObject

File

Linker ExecutableFile

LinkLibraries

A project may consist of multiple source files

Assembler translates each source file separately into an object file

Linker links all object files together with link libraries


Debugger Allows you to trace the execution of a program

Allows you to view code, memory, registers, etc.

You will use the 32-bit Windows debugger


Editor Allows you to create assembly language source files Some editors provide syntax highlighting features and

can be customized as a programming environment


Programmer’s View of a Computer System

Application ProgramsHigh-Level Language

Assembly Language

Operating System

Instruction SetArchitecture

Microarchitecture

Digital Logic Level 0

Level 1

Level 2

Level 3

Level 4

Level 5Increased level of abstraction

Each level hides the

details of the level below it


Programmer's View – 2 Application Programs (Level 5)

Written in high-level programming languages Such as Java, C++, Pascal, Visual Basic . . . Programs compile into assembly language level (Level 4)

Assembly Language (Level 4) Instruction mnemonics are used Have one-to-one correspondence to machine language Calls functions written at the operating system level (Level 3) Programs are translated into machine language (Level 2)

Operating System (Level 3) Provides services to level 4 and 5 programs Translated to run at the machine instruction level (Level 2)


Programmer's View – 3 Instruction Set Architecture (Level 2)

Specifies how a processor functions Machine instructions, registers, and memory are exposed Machine language is executed by Level 1 (microarchitecture)

Microarchitecture (Level 1) Controls the execution of machine instructions (Level 2) Implemented by digital logic (Level 0)

Digital Logic (Level 0) Implements the microarchitecture Uses digital logic gates Logic gates are implemented using transistors


Instruction Set Architecture (ISA) Collection of assembly/machine instruction set of the

machine, Machine resources that can be managed with these

instructions Memory, Programmer-accessible registers.

Provides a hardware/software interface

Flash Movie


Basic Computer Organization Since the 1940's, computers have 3 classic components:

Processor, called also the CPU (Central Processing Unit) Memory and Storage Devices I/O Devices

Interconnected with one or more buses Bus consists of

Data Bus Address Bus Control Bus

Processor(CPU)

Memory

registers

ALU clock

I/ODevice

#1

I/ODevice

#2

data bus

control bus

address bus

CU


Processor consists of Datapath

ALU Registers

Control unit

ALU Performs arithmetic

and logic instructions

Control unit (CU) Generates the control signals required to execute instructions

Implementation varies from one processor to another

Processor

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Synchronizes Processor and Bus operations

Clock cycle = Clock period = 1 / Clock rate

Clock rate = Clock frequency = Cycles per second 1 Hz = 1 cycle/sec 1 KHz = 103 cycles/sec

1 MHz = 106 cycles/sec 1 GHz = 109 cycles/sec

2 GHz clock has a cycle time = 1/(2×109) = 0.5 nanosecond (ns)

Clock cycles measure the execution of instructions

Clock

Cycle 1 Cycle 2 Cycle 3


Memory Ordered sequence of bytes

The sequence number is called the memory address

Byte addressable memory Each byte has a unique address

Supported by almost all processors

Physical address space Determined by the address bus width

Pentium has a 32-bit address bus Physical address space = 4GB = 232 bytes

Itanium with a 64-bit address bus can support Up to 264 bytes of physical address space


Address Space

Address Space is the set of memory locations (bytes) that can be addressed


Address, Data, and Control Bus Address Bus

Memory address is put on address bus If memory address = a bits then 2a locations are addressed

Data Bus: bi-directional bus Data can be transferred in both directions on the data bus

Control Bus Signals control

transfer of data Read request Write request Done transfer

Memory

0123

2a – 1

. . .readwritedone

data bus

address busProcessor

d bits

a bitsAddress Register

Data Register

Bus Control


Memory Read and Write Cycles Read cycle

1. Processor places address on the address bus

2. Processor asserts the memory read control signal

3. Processor waits for memory to place the data on the data bus

4. Processor reads the data from the data bus

5. Processor drops the memory read signal

Write cycle1. Processor places address on the address bus

2. Processor places the data on the data bus

3. Processor asserts the memory write control signal

4. Wait for memory to store the data (wait states for slow memory)

5. Processor drops the memory write signal


Reading from Memory Multiple clock cycles are required Memory responds much more slowly than the CPU

Address is placed on address bus Read Line (RD) goes low, indicating that processor wants to read CPU waits (one or more cycles) for memory to respond Read Line (RD) goes high, indicating that data is on the data bus

Cycle 1 Cycle 2 Cycle 3 Cycle 4

Data

Address

CLK

ADDR

RD

DATA


Memory Devices Volatile Memory Devices

Data is lost when device is powered off RAM = Random Access Memory DRAM = Dynamic RAM

1-Transistor cell + trench capacitor Dense but slow, must be refreshed Typical choice for main memory

SRAM: Static RAM 6-Transistor cell, faster but less dense than DRAM Typical choice for cache memory

Non-Volatile Memory Devices Stores information permanently ROM = Read Only Memory Used to store the information required to startup the computer Many types: ROM, EPROM, EEPROM, and FLASH FLASH memory can be erased electrically in blocks


Processor-Memory Performance Gap

1980 – No cache in microprocessor 1995 – Two-level cache on microprocessor

CPU: 55% per year

DRAM: 7% per year1

10

100

100019

8019

81

1983

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Processor-MemoryPerformance Gap:(grows 50% per year)

Per

form

ance

“Moore’s Law”


The Need for a Memory Hierarchy Widening speed gap between CPU and main memory

Processor operation takes less than 1 ns

Main memory requires more than 50 ns to access

Each instruction involves at least one memory access One memory access to fetch the instruction

A second memory access for load and store instructions

Memory bandwidth limits the instruction execution rate

Cache memory can help bridge the CPU-memory gap

Cache memory is small in size but fast


Typical Memory Hierarchy Registers are at the top of the hierarchy

Typical size < 1 KB Access time < 0.5 ns

Level 1 Cache (8 – 64 KB) Access time: 0.5 – 1 ns

L2 Cache (512KB – 8MB) Access time: 2 – 10 ns

Main Memory (1 – 2 GB) Access time: 50 – 70 ns

Disk Storage (> 200 GB) Access time: milliseconds

Microprocessor

Registers

L1 Cache

L2 Cache

Memory

Disk, Tape, etc

Memory Bus

I/O Bus

Fast

er

Big

ger


Magnetic Disk Storage

Track 0Track 1

Sector

Recording area

Spindle

Direction of rotation

Platter

Read/write head

Actuator

Arm

Track 2

Disk Access Time = Seek Time + Rotation Latency + Transfer Time

Seek Time: head movement to the desired track (milliseconds)

Rotation Latency: disk rotation until desired sector arrives under the head

Transfer Time: to transfer data


Example on Disk Access Time Given a magnetic disk with the following properties

Rotation speed = 7200 RPM (rotations per minute) Average seek = 8 ms, Sector = 512 bytes, Track = 200 sectors

Calculate Time of one rotation (in milliseconds) Average time to access a block of 32 consecutive sectors

Answer Rotations per second Rotation time in milliseconds Average rotational latency Time to transfer 32 sectors Average access time

= 7200/60 = 120 RPS

= 1000/120 = 8.33 ms= time of half rotation = 4.17 ms= (32/200) * 8.33 = 1.33 ms= 8 + 4.17 + 1.33 = 13.5 ms


Input Devices

Logical arrangement of keys0 1 2 3

c d e f

8 9 a b

4 5 6 7

Mechanical switch

Spring

Key Cap

Contacts

Membrane switch

Conductor-coated membrane

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Output Devices

Laser printing

Rollers

Sheet of paper

Light from optical system

Toner

Rotating drum

Cleaning of excess toner

Charging

Heater

Fusing of toner


I/O Controllers I/O devices are interfaced via an I/O controller

I/O controller uses the system bus to communicate with processor I/O controller takes care of low-level operation details


Data Representation Binary Numbers Hexadecimal Numbers Base Conversions Integer Storage Sizes Binary and Hexadecimal Addition Signed Integers and 2's Complement Notation Binary and Hexadecimal subtraction Carry and Overflow Character Storage


Binary Numbers

Digits are 1 and 0 1 = true 0 = false

MSB – most significant bit LSB – least significant bit Bit numbering:

015

1 0 1 1 0 0 1 0 1 0 0 1 1 1 0 0MSB LSB


Binary Numbers Each digit (bit) is either 1 or 0 Each bit represents a power of 2:

Every binary number is a sum of powers of 2


Converting Binary to DecimalWeighted positional notation shows how to calculate the decimal value of each binary bit:

Decimal = (dn-1 2n-1) (dn-2 2n-2) ... (d1 21) (d0 20)

d = binary digit

binary 00001001 = decimal 9:

(1 23) + (1 20) = 9


Convert Unsigned Decimal to Binary

Repeatedly divide the decimal integer by 2. Each remainder is a binary digit in the translated value:

37 = 100101stop when

quotient is zero

least significant bit

most significant bit


Hexadecimal IntegersBinary values are represented in hexadecimal.


Converting Binary to Hexadecimal• Each hexadecimal digit corresponds to 4 binary bits.

• Example: Translate the binary integer 000101101010011110010100 to hexadecimal:


Converting Hexadecimal to Decimal

Multiply each digit by its corresponding power of 16:

Decimal = (d3 163) + (d2 162) + (d1 161) + (d0 160)

d = hexadecimal digit

Examples:

Hex 1234 = (1 163) + (2 162) + (3 161) + (4 160) =

Decimal 4,660

Hex 3BA4 = (3 163) + (11 * 162) + (10 161) + (4 160) =

Decimal 15,268


Converting Decimal to Hexadecimal

Decimal 422 = 1A6 hexadecimal

stop when quotient is zero

least significant digit

most significant digit

Repeatedly divide the decimal integer by 16. Each remainder is a hex digit in the translated value:


Integer Storage Sizes

What is the largest unsigned integer that may be stored in 20 bits?

Standard sizes:


Binary Addition Start with the least significant bit (rightmost bit) Add each pair of bits Include the carry in the addition, if present

0 0 0 0 0 1 1 1

0 0 0 0 0 1 0 0

+

0 0 0 0 1 0 1 1

1

(4)

(7)

(11)

carry:

01234bit position: 567


Hexadecimal Addition Divide the sum of two digits by the number base (16). The quotient becomes

the carry value, and the remainder is the sum digit.

36 28 28 6A42 45 58 4B78 6D 80 B5

11

21 / 16 = 1, remainder 5

Important skill: Programmers frequently add and subtract the addresses of variables and instructions.


Signed Integers Several ways to represent a signed number

Sign-Magnitude 1's complement 2's complement

Divide the range of values into 2 equal parts First part corresponds to the positive numbers (≥ 0) Second part correspond to the negative numbers (< 0)

Focus will be on the 2's complement representation Has many advantages over other representations Used widely in processors to represent signed integers


Two's Complement Representation8-bit Binary

valueUnsigned

valueSignedvalue

00000000 0 0

00000001 1 +1

00000010 2 +2

. . . . . . . . .

01111110 126 +126

01111111 127 +127

10000000 128 -128

10000001 129 -127

. . . . . . . . .

11111110 254 -2

11111111 255 -1

Positive numbers Signed value = Unsigned value

Negative numbers Signed value = 2n – Unsigned value n = number of bits

Negative weight for MSB Another way to obtain the signed

value is to assign a negative weight to most-significant bit

= -128 + 32 + 16 + 4 = -76

1 0 1 1 0 1 0 0

-128 64 32 16 8 4 2 1


Forming the Two's Complement

Sum of an integer and its 2's complement must be zero:

00100100 + 11011100 = 00000000 (8-bit sum) Ignore Carry

The easiest way to obtain the 2's complement of a binary number is by starting at the LSB, leaving all the

0s unchanged, look for the first occurrence of a 1. Leave this 1 unchanged and complement all the bits after it.

starting value 00100100 = +36

step1: reverse the bits (1's complement) 11011011

step 2: add 1 to the value from step 1 + 1

sum = 2's complement representation 11011100 = -36


Sign BitHighest bit indicates the sign. 1 = negative, 0 = positive

If highest digit of a hexadecimal is > 7, the value is negative

Examples: 8A and C5 are negative bytes

A21F and 9D03 are negative words

B1C42A00 is a negative double-word


Sign ExtensionStep 1: Move the number into the lower-significant bits

Step 2: Fill all the remaining higher bits with the sign bit This will ensure that both magnitude and sign are correct Examples

Sign-Extend 10110011 to 16 bits

Sign-Extend 01100010 to 16 bits

Infinite 0s can be added to the left of a positive number Infinite 1s can be added to the left of a negative number

10110011 = -77 11111111 10110011 = -77

01100010 = +98 00000000 01100010 = +98


Two's Complement of a Hexadecimal

To form the two's complement of a hexadecimal Subtract each hexadecimal digit from 15

Add 1

Examples:

2's complement of 6A3D = 95C2 + 1 = 95C3

2's complement of 92F0 = 6D0F + 1 = 6D10

2's complement of FFFF = 0000 + 1 = 0001

No need to convert hexadecimal to binary


Binary Subtraction When subtracting A – B, convert B to its 2's complement Add A to (–B)

0 0 0 0 1 1 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 1 0 1 1 1 1 1 1 1 0 (2's complement)

0 0 0 0 1 0 1 0 0 0 0 0 1 0 1 0 (same result)

Carry is ignored, because Negative number is sign-extended with 1's You can imagine infinite 1's to the left of a negative number Adding the carry to the extended 1's produces extended zeros

Practice: Subtract 00100101 from 01101001.

– +


Hexadecimal Subtraction When a borrow is required from the digit to the left,

add 16 (decimal) to the current digit's value

Last Carry is ignored

Practice: The address of var1 is 00400B20. The address of the next variable after var1 is 0040A06C. How many bytes are used by var1?

C675A247242E

-1

-

16 + 5 = 21

C6755DB9 (2's complement)242E (same result)

1

+1


Ranges of Signed IntegersThe unsigned range is divided into two signed ranges for positive and negative numbers

Practice: What is the range of signed values that may be stored in 20 bits?


Carry and Overflow Carry is important when …

Adding or subtracting unsigned integers Indicates that the unsigned sum is out of range Either < 0 or >maximum unsigned n-bit value

Overflow is important when … Adding or subtracting signed integers Indicates that the signed sum is out of range

Overflow occurs when Adding two positive numbers and the sum is negative Adding two negative numbers and the sum is positive Can happen because of the fixed number of sum bits


0 1 0 0 0 0 0 0

0 1 0 0 1 1 1 1+

1 0 0 0 1 1 1 1

79

64

143(-113)

Carry = 0 Overflow = 1

1

1 0 0 1 1 1 0 1

1 1 0 1 1 0 1 0+

0 1 1 1 0 1 1 1

218 (-38)

157 (-99)

119


111

Carry and Overflow Examples We can have carry without overflow and vice-versa Four cases are possible

1 1 1 1 1 0 0 0

0 0 0 0 1 1 1 1+

0 0 0 0 0 1 1 1

15

245 (-8)

7


11111

0 0 0 0 1 0 0 0

0 0 0 0 1 1 1 1+

0 0 0 1 0 1 1 1

15

8

23


1


Character Storage Character sets

Standard ASCII: 7-bit character codes (0 – 127) Extended ASCII: 8-bit character codes (0 – 255) Unicode: 16-bit character codes (0 – 65,535) Unicode standard represents a universal character set

Defines codes for characters used in all major languages Used in Windows-XP: each character is encoded as 16 bits

UTF-8: variable-length encoding used in HTML Encodes all Unicode characters Uses 1 byte for ASCII, but multiple bytes for other characters

Null-terminated String Array of characters followed by a NULL character


Printable ASCII Codes0 1 2 3 4 5 6 7 8 9 A B C D E F

2 space ! " # $ % & ' ( ) * + , - . /3 0 1 2 3 4 5 6 7 8 9 : ; < = > ?4 @ A B C D E F G H I J K L M N O5 P Q R S T U V W X Y Z [ \ ] ^ _6 ` a b c d e f g h i j k l m n o7 p q r s t u v w x y z { | } ~ DEL

Examples: ASCII code for space character = 20 (hex) = 32 (decimal) ASCII code for 'L' = 4C (hex) = 76 (decimal) ASCII code for 'a' = 61 (hex) = 97 (decimal)


Control Characters The first 32 characters of ASCII table are used for control Control character codes = 00 to 1F (hex)

Not shown in previous slide

Examples of Control Characters Character 0 is the NULL character used to terminate a string Character 9 is the Horizontal Tab (HT) character Character 0A (hex) = 10 (decimal) is the Line Feed (LF) Character 0D (hex) = 13 (decimal) is the Carriage Return (CR) The LF and CR characters are used together

They advance the cursor to the beginning of next line

One control character appears at end of ASCII table Character 7F (hex) is the Delete (DEL) character


Terminology for Data Representation

Binary Integer Integer stored in memory in its binary format Ready to be used in binary calculations

ASCII Digit String A string of ASCII digits, such as "123"

ASCII binary String of binary digits: "01010101"

ASCII decimal String of decimal digits: "6517"

ASCII hexadecimal String of hexadecimal digits: "9C7B"


Summary Assembly language helps you learn how software is constructed at

the lowest levels Assembly language has a one-to-one relationship with machine

language An assembler is a program that converts assembly language

programs into machine language A linker combines individual files created by an assembler into a

single executable file A debugger provides a way for a programmer to trace the execution

of a program and examine the contents of memory and registers A computer system can be viewed as consisting of layers. Programs

at one layer are translated or interpreted by the next lower-level layer Binary and Hexadecimal numbers are essential for programmers

working at the machine level.

Basic Concepts

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