Write Your Own Operating System Tutorial(4) (轉)
Now is the time you’ve all been waiting for. Finally we get to the classic “first” program. Every decent programming book has a “Hello, World” program, and now we know enough to make a “Hello, World” operating system. If you have done some experimenting on your own and have already done this, then you may want to skthis lesson. We will create a function to print a string and use it to display our message.
It will get tedious to print one character at a time to the screen, so we’ll create a function to print a zero-tenated string to the screen. This is just a simple l that prints all the character in a string one at a time.
; ---------------------------------------------:namespace prefix = o ns = "urn:schemas--com::office" />
; Print a null-terminated string on the screen
; ---------------------------------------------
putstr:
lodsb ; AL = [DS:SI]
or al, al ; Set zero flag if al=0
jz putstrd ; jump to putstrd if zero flag is set
mov ah, 0x0e ; vo function 0Eh (print char)
mov bx, 0x0007 ; color
int 0x10
jmp putstr
putstrd:
retn
Now, a little on how to use this function. First you have to load the address of the first character of the string into the register SI. Then simply call this subroutine putstr.
You can create a string like this in your assembly file.
msg 'Hello, World!', 0
The zero on the end terminates the string. Then you can print the string to the screen using the following instructions.
mov si, msg ; Load address of message
call putstr ; Print the message
There is just one more thing that needs to be set up before this will work. The address msg, loaded into the register SI, is actually an offset off the beginning of the beginning of the segment that is pointed to by the register DS. So, before you can use the address msg, you must set up the current data segment. For now, we will use flat addressing from the bottom of physical RAM. To set the data segment to start from the bottom, set the DS register to zero. The following two instructions will do this.
xor ax, ax ; Zero out ax
mov ds, ax ; Set data segment to base of RAM
Try putting all of these parts together using the file from as a starting point. Then, using the same method described in Lesson 3, assemble your file, copy it to your floppy disk and boot with it. Have fun. If you get stuck, you can look at my solution, , but it’s no fair peeking until you’ve tried!
Once you have finished, proceed to the next lesson where we will learn how to make our operating system interactive.
來自 “ ITPUB部落格 ” ,連結:http://blog.itpub.net/10752043/viewspace-993852/,如需轉載,請註明出處,否則將追究法律責任。
相關文章
- operating-system structuresStruct
- Is programming an Operating System so hard?
- What’s your own way of spending two-day weekend?
- mysql 啟動錯誤(InnoDB: Operating system error number 13 )MySqlError
- 【build your own xxx】實現你自己的bind函式UI函式
- 【build your own xxx】實現你自己的call和applyUIAPP
- 作業系統-Operating-System第一章:概述作業系統
- Pytorch | Tutorial-03 資料轉換PyTorch
- 轉載:System:System.arraycopy方法詳解
- Zeiss tutorial
- COMP3230 Principles of Operating Systems
- simvison tutorial pdf
- Batch Scripting TutorialBAT
- 【轉載】System_Verilog列印格式
- RabbitMQ tutorial - "Hello world!"MQ
- System.Linq.Dynamic字串轉委託字串
- 作業系統概念(Operating System Concepts Ninth Edition恐龍書)第三章課後非程式設計題答案作業系統程式設計
- Linux核心同步機制之(五):Read Write spin lock【轉】Linux
- Your title
- linux symbolic link attack tutorialLinuxSymbol
- [譯]A Simple CSS Animation TutorialCSS
- MySQL double writeMySql
- [Javascript] Write .call()JavaScript
- MongoDB Write ConcernMongoDB
- hio_write
- Scan Your Truck Using Nexiq Adapter: Simplifying Your Diagnostic ProcessAPT
- Operating Systems: Principles and Practice 2nd ed. Edition
- Tutorial: Create SQL Cluster(FCI) on RHELSQL
- Tutorial: Add a node to SQL cluster on RHELSQL
- Hive Tutorial 閱讀記錄Hive
- Prettier your projectProject
- Offering Your Seat
- Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQLMySqlJDBCExceptionError
- 閉包的理解-from my own opinion
- Basic "info" tutorial in stand-alone program
- Structuring Your TensorFlow ModelsStruct
- translate-your-site
- deploy-your-site
- your Android sdk is missingAndroid