1. Assembly Language for Intel-Based Computers
Chapter 1: Basic Concepts

2. Chapter Overview Welcome to Assembly Language Virtual Machine Concept
Data Representation
Boolean Operations

3. Welcome to Assembly Language
Some Good Questions to Ask
Assembly Language Applications

4. Questions to Ask Why am I learning Assembly Language?
Assembly language is the oldest programming languages
Bears the closest resemblance to the native language of the computer
provides direct access to a computer’s hardware, make it easier to understand computer architecture and operating systems
What background should I have?
-Computer programming basic

5. Questions to Ask What is an assembler?
An assembler is a program that converts source code programs from assembly language into machine language
Assembler can optionally generate source listing file with line numbers, memory address, source code statement, and cross reference listing of symbols and variables used in a program
Companion program is linker and debugger
Linker will combine individual files created by an assembler into single executable program
Debugger provide way to trace the execution of a program and examine the content of memory

6. Questions to Ask What hardware/software do I need?
Computer-Intel386,Intel486 or one of pentium processors
Operating systems-Ms Windows, Ms-Dos or Linux running a DOS emulator
Editor-notepead, textpad, visual studio editor
Assembler-Ms Assembler (MASM 6.15), Borland Turbo Assembler (TASM)
Linker-Ms 16-bit linker (link.exe) or Ms 32-bit linker (link32.exe)
Debugger-Codeview, Turbo Debugger

7. Questions to Ask What types of programs will I create?
16-bit real address mode-running in pure MS-DOS or DOS emulator
32-bit protected mode-using Ms Windows, display both text and graphics
What will I learn?
Basic principles of computer architecture
Basic boolean logic
Manage memory
Data representation
How application program communicate with the computer OS via interrupt handlers, system calls and ect.
How OS load and execute application program

8. Welcome to Assembly Language (cont)
How does assembly language (AL) relate to machine language?
Machine language is a numeric language that is spesifically understood by a computer processor (CPU)
Assembly language consist of statements that use short mnemonics such as ADD, MOV,SUB and CALL
Assembly language has one-to-one relationship with machine language
How do C++ and Java relate to AL?
High level language have a one-to many relationship with both assembly language and machine language

9. Welcome to Assembly Language (cont)
Is AL portable?
A language whose source programs can be compiled and run on wide variety of computer systems is said to be portable. Assembly language tied to specific processor family.
Why learn AL?
Embedded systems program
Optimize both space and runtime speed
Understand interaction between computer hardware, OS and application program
Create device driver

10. Assembly Language Applications
Some representative types of applications:
Business application for single platform
Hardware device driver
Business application for multiple platforms
Embedded systems & computer games
(see next panel)

11. Comparing ASM to High-Level Languages

12. Assembling, Linking, and Running Programs
Assemble-Link-Execute Cycle
make32.bat
Listing File
Map File

13. Assemble-Link Execute Cycle
The following diagram describes the steps from creating a source program through executing the compiled program.
If the source code is modified, Steps 2 through 4 must be repeated.

14. Example linked linkage file

15. Listing File Use it to see how your program is compiled Contains
source code
addresses
object code (machine language)
segment names
symbols (variables, procedures, and constants)
Example: addSub.lst

16. Map File Information about each program segment:
starting address
ending address
size
segment type
Example: addSub.map (16-bit version)