Gavin's Guide to 80x86 Assembly

This was originally written for the Phil Inch's Game Developer's Magazine and after getting lots of positive feedback I expanded and improved it. I have spent a lot of time working on this and would appreciate hearing from you if you like it.

Here is some of the feedback I have recieved.

If you want to contact me then e-mail me at: gavin@senator.demon.co.uk or on CompuServe at 100767,1325

Useful Resources

List of Instructions and timings

If you have TASM then the "Borland Turbo Assembler Quick Reference" has a list of instructions and timings up to 486. The "Intel Pentium Family User's Manual: Volume 3" is equally useful.

• Borland's Web Site
• Intel's Web Site

List of Interrupts

There are several books that have this information but the most up to date is Ralf Brown's Interrupt list available freely in four parts at:

ftp://x2ftp.oulu.fi/pub/msdos/programming/docs/interXX[a-d].zip

where XX is the version (go there).

A book that covers both these topics and is a useful assembly reference is:

The Revolutionary Guide to Assembly Language
Vitaly Maljugin, Jacov Izrailevich et al
Wrox Press
ISBN: 1-874416-12-5

Table of Contents

Part I - Introduction to the hardware

Overview of the 80x86 Family · Representation of numbers in binary · Registers · Segments and offsets · The Stack

Part II - An Introduction to Assembly Instructions

Push and Pop: Two Instructions to use the Stack · Types of Operand · Some Instructions that you will need to know · Your first assembly program · Compilation Instructions

Part III - Input and Control Flow

Making things easier · Keyboard Input · Printing a Character · Control Flow · Jump on Condition Instructions · Example Program

Part IV - Procedures and Macros

Some instructions that you need to know · Introduction to Procedures · Procedures that pass parameters · What are "Memory Models"? · Macros · Macros with parameters

Part V - Files

File Functions · How to save the file handle · Using the FindFirst and FindNext Functions

Part VI - Strings, Shifts and Debuggers

String Instructions · How to find out the DOS Version · Multiple Pushes and Pops · The PUSHA/PUSHAD and POPA/POPAD Instructions · Using Shifts for faster Multiplication and Division · Loops · How to use a debugger

Part VII - Writing to the Screen

More output in text modes · Mode 13h · First check that mode 13h is possible · Setting the Video Mode · Some Optimizations

In the meantime you can contact me if you need any help.

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