ProgramsProgramsProgramsPrograms usingusingusingusing DOS
Interrupt Functions DOS Interrupt Functions DOS Interrupt Functions
DOS Interrupt FunctionsPresentation by:C. Thiruvenkatesan C.
Thiruvenkatesan C. Thiruvenkatesan C. ThiruvenkatesanAssociate
Professor / ECE SSN College of EngineeringPrograms for Programs for
Programs for Programs for1. 1. 1. 1. Displaying System Time
Displaying System Time Displaying System Time Displaying System
Time2. 2. 2. 2. Displaying System Date Displaying System Date
Displaying System Date Displaying System Date3. 3. 3. 3. Displaying
System Day Displaying System Day Displaying System Day Displaying
System Day4. 4. 4. 4. Password Checking Password Checking Password
Checking Password Checkingusingusingusingusing DOS Interrupt
Functions DOS Interrupt Functions DOS Interrupt Functions DOS
Interrupt FunctionsDOS Interrupts Used: DOS Interrupts Used: DOS
Interrupts Used: DOS Interrupts Used:INT 21 H / AH=2C H - GET
SYSTEM TIMEReturn: CH = Hour CL = Minute DH = Second DL = 1/100
secondsINT 21 H / AH=2A H - GET SYSTEM DATEReturn: CX = Year
(1980-2099). DH = Month. DL = Day. AL = Day of week (00h=Sunday)INT
21 H / AH=02 H - DISPLAY OUTPUT (a single character)Outputs the
character in DL to the standard output device.INT 21 H / AH= 09H
DISPLAY OUTPUT (STRING)Sends the characters in the string to the
standard output device.The character string in memory must be
terminated by a $ (24H).INT 21 H / AH=08 H - Wait for console input
without echo Terminates the current process and transfers control
to the invoking process.INT 21 H / AH=4C H - TERMINATE A PROCESS
(EXIT)Terminates the current process and transfers control to the
invoking process.Title Program to Display System Time in HH/MM/SS
format.MODEL SMALL.DATA.CODESTART:MOV AX, @DATAMOV DS, AX; Hour
PartHOUR: MOV AH, 2CH; To get System TimeINT 21HMOV AL, CH ; Hour
is in CHAAMMOV BX, AXCALL DISPMOV DL, ':'MOV AH, 02H; To Print ":"
in DOSINT 21H1; Minutes PartMINUTES: MOV AH, 2CH; To get System
TimeINT 21HMOV AL, CL ; Minutes is in CLAAMMOV BX, AXCALL DISPMOV
DL, ':'; To Print ":" in DOSMOV AH, 02HINT 21H; Seconds
PartSeconds: MOV AH, 2CH; To get System TimeINT 21HMOV AL, DH ;
Seconds is in DHAAMMOV BX, AXCALL DISP1; To terminate the
ProgramMOV AH, 4CH ; To Terminate the ProgramINT 21H; Display
PartDISP PROCMOV DL, BH; Since the values are in BX, BH PartADD DL,
30H ; ASCII AdjustmentMOV AH, 02H; To Print in DOSINT 21HMOV DL, BL
; Since the values are in BX, BL Part ADD DL, 30H ; ASCII
AdjustmentMOV AH, 02H ; To Print in DOSINT 21HRETDISP ENDP; End
Display ProcedureEND START ; End of MAIN1Title Program to Display
System Date in DD/MM/YYYY format.MODEL SMALL.DATA.CODESTART:MOV AX,
@DATAMOV DS, AX; Date PartDate: MOV AH, 2AH; To get System DateINT
21HMOV AL, DL ; Date is in DLAAMMOV BX, AXCALL DISPMOV DL, '/'MOV
AH, 02H; To Print ":" in DOSINT 21H2; Month PartMonth: MOV AH, 2AH;
To get System DateINT 21HMOV AL, DH ; Month is in DHAAMMOV BX,
AXCALL DISPMOV DL, '/'; To Print ":" in DOSMOV AH, 02HINT 21H2;
Year PartYear: MOV AH, 2AH; To get System DateINT 21HMOV AL, 14H;
Year is in CX, first partAAMMOV BX, AXCALL DISPMOV AH, 2AH; To get
System DateINT 21HADD CX, 0F830H ; To negate the effects of 16-bit
valueMOV AL, CL; Year is in CX, second partAAMMOV BX, AXCALL DISP2;
To terminate the ProgramMOV AH, 4CH ; To Terminate the ProgramINT
21H; Display PartDISP PROCMOV DL, BH; Since the values are in BX,
BH PartADD DL, 30H ; ASCII AdjustmentMOV AH, 02H; To Print in
DOSINT 21HMOV DL, BL ; BL Part ADD DL, 30H ; ASCII AdjustmentMOV
AH, 02H ; To Print in DOSINT 21HRETDISP ENDP; End Display
ProcedureEND START ; End of MAIN2TitleAn Assembly Language Program
to Display System Day.MODEL SMALL.DATADMSG0 DB 10,13,'SUNDAY
','$'DMSG1 DB 10,13,'MONDAY ','$'DMSG2 DB 10,13,'TUESDAY','$'DMSG3
DB 10,13,'WEDNESDAY','$'DMSG4 DB 10,13,'THURSDAY ','$'DMSG5 DB
10,13,'FRIDAY ','$'DMSG6 DB 10,13,'SATURDAY ','$'3.CODESTART:MOV
AX, @DATAMOV DS, AXMOV AH, 2AH; To get System DateINT 21HCMP AL,
00H ; Day is in ALJNE NXT1MOV DX, OFFSET DMSG0CALL DISPNXT1: CMP
AL, 01H ; Day is in ALJNE NXT2MOV DX, OFFSET DMSG1CALL DISPNXT2:
CMP AL, 02H ; Day is in ALJNE NXT3MOV DX, OFFSET DMSG2CALL
DISP3NXT3: CMP AL, 03H ; Day is in ALJNE NXT4MOV DX, OFFSET
DMSG3CALL DISPNXT4: CMP AL, 04H ; Day is in ALJNE NXT5MOV DX,
OFFSET DMSG4CALL DISPNXT5: CMP AL, 05H ; Day is in ALJNE NXT6MOV
DX, OFFSET DMSG5CALL DISPNXT6: CMP AL, 06H ; Day is in ALJNE
TERMIMOV DX, OFFSET DMSG6CALL DISP3; To terminate the ProgramTERMI:
MOV AH, 4CH ; To Terminate the ProgramINT 21H; Display
PartDISPPROCMOV AH, 09H ; To Print in DOSINT 21HRETDISPENDP; End
Display ProcedureEND START ; End of MAIN3Program to Display System
Time in HH/MM/SS formatProgram to Display System Date in DD/MM/YYYY
formatProgram to Display System Day321TITLE Program to Check
whether the Password entered is correct or not;; PASSWORD IS
SSNECEDATASEGMENTPASSWORD DB 'SSNECE'LEN EQU ($-PASSWORD)RMSG1 DB
10,13,'ENTER YOUR PASSWORD: $'CMSG2 DB 10,13,01,' GOOD, CORRECT
PASSWORD ! ! ',02,'$'ICMSG3 DB 10,13,'SORRY, INCORRECT
PASSWORD!$'NEW DB 10,13,'$'INST DB 10
DUP(0)DATAENDS4CODESEGMENTASSUME CS:CODE, DS:DATASTART:MOV AX,
DATAMOV DS, AXLEA DX, RMSG1MOV AH, 09HINT 21HMOV SI, 00HBACK1:MOV
AH, 08HINT 21HCMP AL, 0DH ; check for carriage return JE SKIP1MOV
[INST+SI], ALMOV DL,'*'MOV AH, 02HINT 21HINC SIJMP BACK14SKIP1:MOV
BX, 00HMOV CX, LENCHECK:MOV AL, [INST+BX]MOV DL, [PASSWORD+BX]CMP
AL, DLJNE FAILINC BXLOOP CHECKLEA DX, CMSG2MOV AH, 09HINT 21HJMP
FINISH4FAIL:LEA DX, ICMSG3MOV AH, 09HINT 21HFINISH:MOV AH, 4CHINT
21HCODEENDSEND STARTEND4
