Coal 20-int21 h in Assembly Programming
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This document provides a summary of a lecture on computer organization and assembly language. It discusses BIOS interrupt 21H function calls for displaying and inputting characters. Specific functions covered include displaying a string using option 09, displaying a single character with option 02, accepting single character input with option 01 and echoing, accepting buffered input with option 0AH, and non-echoed single character input with option 07. It also mentions the LABEL directive for defining variables and provides a chapter review on BIOS interrupt 21H programming.
Coal 20-int21 h in Assembly Programming
- 1. COMPUTER ORGANIZATION & ASSEMBLY LANGUAGE LECTURE ON 21H WEEK 13 PRACTICAL BY MUHAMMAD JAFER 1
- 2. INT 21H BIOS-ROM based DOS INT 21H function Calls Appendix D contains all of the functions Displaying & Inputting Function 2
- 3. CHARACTER DISPLAY Option 09 DATA1 = This earth is but one country,$ AH = 09 DX = OFFSET DATA1 INT 21H Importance of $ Option 02 AH = 02 DL = J INT 21H Single Character 3
- 4. CHARACTER INPUT Option 01 AH = 01 INT 21H Result : AL= input Character Echoing Option 0AH DATA1 DUP 6,?,6 (FF) AH = 0AH DX = OFFSET DATA1 INT 21H Buffer Concepts 1st Byte = Size of Buffer 2nd Byte = No of Characters 3rd Bytes onwards = Data 4
- 5. CHARACTER INPUT (CONT) Option 07 AH = 07 INT 21H Result : AL= input Character No Echo 5
- 6. LABEL DIRECTIVE Name LABEL Attribute JOE LABEL Byte WORD,DWORD,FWORD,QWORD,TBYTE 6
- 7. CHAPTER REVIEW The x86 PC Assembly Language, Design & Interfacing Chapter # 4 BIOS INT 21H PROGRAMMING 7