ASSEMBLY LANGUAGE PROGRAMMING
Course Objectives â€˘ Identify the major component of a PC-based system, describe the steps involving in assembling, linking, and executing a program â€˘ Write/Debug programs in assembly language to perform the given task and run them
Textbook/Technology requirement Textbook: IBM PC Assembly Language and Programming. Peter Abel. 2001. Fifth Edition. Prentice Hall. ISBN: 0-13-030655-X Software: Emu8086 microprocessor assembler and emulator software. Available at www.emu8086.com
Introduction Tell me about yourself and what you expect to get out from this course
Course detail - Topics Write a program in assembly language
Understanding of a PC-based system
Fundamentals of assembly language & program
What does it take to success -Attend the class regularly and actively participate in the class discussion (ask questions, answer questions, etc..) -Donâ€™t give up on programming assignments. Pay attention to detail -Try many options when doing programming assignments
Fundamental of PC Hardware and Software
Basic features of PC Hardware • Binary and Hexadecimal Number Systems – Bits/bytes – Binary number systems – Hexadecimal – ASCII
• PC Components – Processor – Memory
Bits/bytes and Binary system • Bits: 0(off) & 1(on) • Bytes: – Represents a storage location in memory and devices. – 8 bits => 28 combination of 0/1.
Bits/bytes and Binary system Address
40 Husky Road Storrs, CT 06329
00000100 00000000 Word Doubleword Quadword Paragraph Kilobyte Megabyte
Bits/bytes and Binary system Bit value
Negative binary numbers 2â€™s complementâ€™s notation
01010101 10101010 Add
10101011 Reverse the bit values and add 1
1. What is the value of 01010101? 2. How to represent -25 in 2â€™s complement notation?
Bits/bytes and Binary system Bit value
Parity bit: forcing the number of bits always odd Example:
Parity bit = 1 00010101 Parity bit = 0
Hexadecimal presentation • Disadvantage of binary representation: – Is not “user-friendly” – Complicated when computing manually
• Hexadecimal representation
Hexadecimal presentation Hexadecimal arithmetic 7+1=8 7+2=9 7+3=A 7+4=B 7+8=F 7+9=?
Practice • Convert from decimal to hexadecimal 23 = ???? 254 = ???? • Adding hexadecimal value 13B4H + 0033H = ???? DCBEH + 35B5H = ????
Popular coding systems to represent data ASCII—American
Standard Code for Information Interchange EBCDIC—Extended Binary Coded Decimal Interchange Code Unicode—coding scheme capable of representing all world’s languages
Conversion from letter to binary format and back Step 1.
The user presses the capital letter D (shift+D key) on the keyboard.
Step 4. After processing, the binary code for the capital letter D is converted to an image, and displayed on the output device.
An electronic signal for the capital letter D is sent to the system unit.
Step 3. The signal for the capital letter D is converted to its ASCII binary code (01000100) and is stored in memory for processing.
PC Components speaker
printer speaker monitor keyboard modem
PC Components ď‚°
What are two main components on the motherboard? Central Processing Unit (CPU) Also called a processor Carries out instructions that tell computer what to do
Memory Temporary holding place for data and instructions
Central processing unit (CPU) (Processor) Interprets
and carries out basic instructions that operate a computer
Control unit directs and coordinates operations in computer Arithmetic logic unit (ALU) performs arithmetic, comparison, and logical operations
Processor Control Control Unit Unit
Arithmetic Arithmetic Logic Logic Unit Unit (ALU) (ALU) Instructions Data Informatio n
Memory Instructions Data Informatio n
Memory • •
Temporary storage place for data, instructions, and information Consists of one or more chips on the motherboard or some other circuit board Operating system
Three basic items stored in memory
Size of memory is measured by the number of bytes available • Kilobyte - 1,024 bytes • Megabyte – approximate one million bytes
Memory What are the two types of memory in the system unit?
volatile Volatile memory Memory Loses Loses its itscontents contents when when the computer's the computer's power ispower turnedis off turned off
nonvolatile memory Does not lose its contents when the computerâ€™s power is turned off
Memory What is random access memory (RAM)? Memory chips that can be read from and written to by the processor and other devices When the computer starts, operating system files are loaded from a hard disk into RAM As additional programs and data are requested, they also load from storage into RAM
Most RAM is volatile
Addressing data in Memory • Difference between address of a memory Location and its content • Processor stores the data in memory in reverse by sequence • Two types of addressing schemes absolute address segment-offset address
Segment • • • • •
Code segment (CS) Data segment (DS) Stack segment (SS) Extra segment (ES) Actual address = segment address + offset
Registers • Segment register – CS,DS,SS,ES, FS and GS
• Pointer register – IP,SP,BP
• General purpose register – AX,BX,CX,DX
• Index register – SI, DI
OF, DF, IF, SF, ZF,AF,PF,CF If cleared: NV,UP,EI,PL,NZ,NA,PO,NC If set: OV,DN,EI,NG,ZR,AC,PE,CY