zen.txt

一个操作系统启动代码

ZEN.txt Overview - Assembler (80286+) Example # 003

Project  :      Bootable asm example
Author   :      Andre v.d. Merwe
EMail    :      <[e-mail]> or <[e-mail]>
Date     :      04-Feb-1999

Please resend any changes or enhancements to the original author.



Overview:
   The three asm file included in this example show what is required for a simple
   bootable application. 
   
   bm.asm    - An application to write the other files to a disk
   boot.asm  - The app that is executed automatically at bootup
   dump.asm  - App executed by boot.asm at bootup. 
   utils.asm - Functions used by other files

   
   At bootup sector 0, track 1 is loaded to 0000:7c00 and executed. 
   This is where boot.com must be located. It will then load dump.com
   to 2000:0100 and execute it.

   There is nothing special about the segment 2000, but there is a good
   reason I loaded the file to offset 100h. A normal dos com file is always
   loaded to offset 100h. This means that you can debug dump.com using a 
   normal dos debugger. When you have it working you can then use it as is
   for the boot sequence. 
   
   [Remember that dos is not loaded at bootup so you can NOT use any dos
   functions (int 21h etc)! You need to use BIOS calls and do most of the
   work yourself.]
   
   BTW if you want to debug a com file with debug info use the following commands
   tasm /z /zi  /(whatever flags you use)  - TASM with debug info
   tlink /v /(whatever flags you use)      - TLINK as an exe with debug info
   tdstrip -c -s (whatever)                - Strip debug info from exe and create a com file

   
   To use this demo, compile the 3 asm files (bm, dump and boot)
   Insert a disk.
   Type "bm 0 1 boot.com"   (writes boot.com so that it will be loaded at bootup)
   Type "bm 1 1 dump.com"   (writes dump.com so that it will be loaded by boot.com)

   Reboot
  

Origional Compiler:
    TASM 5.0   



Programmer:

   Andre v.d. Merwe
   email  : <[e-mail]> or <[e-mail]>


ZEN Library:
	To receive more information regarding the ZEN Library, 
	Look at the ZEN Library home page at

        http://users.iafrica.com/d/da/dart/zen/zen.html
        <[e-mail]> or <[e-mail]>




Copyright Notices:
	
	As with all submissions to the ZEN Library, this program is free
	software; you can redistribute it and/or modify it under the terms
        of the GNU General Public License 2 as published by the Free Software
	Foundation.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	To recieve a copy of the GNU General Public License
	write to:
		Free Software Foundation, Inc.,
		675 Mass Ave,
		Cambridge, MA 02139, USA.