Assembly Language Tutorial

 
 
 

Instructions

Input - Output Instructions

Display a character Read a character and display it on new line Display string Read digit, compute and display sum w/o variable Read digit, display difference w/o variable Read digit, compute, display sum using variable Read digit, display difference using variable Convert lower case letter in to upper case Read character, display in new line - user prompt Read 1st, middle, last initial - down left margin Read one hex digit, display next line in decimal Display 10*10 solid box asterisk - INT 21H and 9H Read 3 char show in middle of 11*11 box, beep comp

Flow Control Instructions

Print ASCII characters Print counting from 0 to 9 Print upper case letters from A to Z Print lower case letters from a to z in reverse Read letter print if it is \'?\' - simulation of if Read char print smallest - simulation of if-else Positive, negative num- simulation of switch-case Print upper case char - simulation of if-else then Simulation of if-else then structure Print ASCII characters - for loop simulation Print upper case A to Z - while loop simulation Print upper case A to Z - Do while loop simulation Read letters display in next line in alpha order Display digit in next line if fail prompt message Read hex digit display on next line in decimal Display capital letter in string alphabetically Show longest sequence consecutive alphabetically

Logic - Shift - Rotate Instructions

Convert upper to lower case - OR logic instruction Convert lower to upper - AND logic instruction Display even or odd number - TEST instruction Multiply content of AL by 8 - SHL instruction Divide content of AL by 4 - SHR instruction Store binary- BX,count bit value 1 w/o changing BX Read binary num, reverse its bit pattern Read binary number store in BX and display Read char- show ASCII in binary- 1 bit in ASC code Read char print ASCII in HEX till- carriage return Read HEX number and print in binary next line Read binary number and print in HEX next line Read 2 binary number and print its sum in binary Read 2 unsigned HEX num and print their sum Read string of decimal digit print sum in HEX Read str of char ter by CR show reverse order Read character using procedure goto next line Binary form & reverse bit of num - procedures Product by ADD, SHIFT instruction - procedure Display text with letters in each word reversed Validate expression READ store bin num in AX, RANDOM, WRITE

Multiplication - Division Instructions

Print factorial in binary form - MUL instruction Print num decimal form - DIV, OUTDEC proc Print factorial in decimal form - MUL, DIV instru Print num next line - proc for DECIMAL i/o Proc INDEC and OUTDEC, handle BackSpace key Proc INDEC and OUTDEC - files - INCLUDE instru Print factorial in dec form - MUL, DIV instruction Proc INDEC, OUTDEC - Handle OverFlow Read time in seconds display time HH:MM:SS Express - quarter, dime, nickel, pennie Read fraction form M/N print N decimal place GCD of two integers M and N

Arrays - Addressing Modes

Sum of array - sum in AX - Register Indirect Mode Initialize array with 0 using DUP instruction Enter an array of size 10 and display it Declare, initialize, print 2D array of size 5x5 Enter 2D array of 5x5 in row major order, print Print 3rd R x 4th C using Register Indirect Mode Display reversing array contents using STACK Reverse content of array - Register Indirect Mode Sort array using Bubble Sort method Sort an array using Select Sort method Print 2D array of size 4x5 in row major order Print 2D array of size 4x5 in column major order 2D arr clear 3rd row 4th column - Based Index Mode Compute class average on each exam Print name each student, average of 4 exams Insert single characters into array - it is sorted

String Instructions

Copy string into another using MOVSB, REP Read string, stores in variable using STOSB Display string using instruction LODSB Store display str - proc READ_STR, DISP_STR Count no of vowels constants - SCASB, REPNE

General Programs

Get and display the current system time
 
 
 .MODEL SMALL
 .STACK 100H

 .DATA
   PROMPT_1  DB  \'Enter the number in binary form (max digit=16) : $\'
   PROMPT_2  DB  \'The given number in original bit pattern is : $\'
   PROMPT_3  DB  \'The given number in reverse bit pattern is  : $\'

 .CODE
   MAIN PROC
     MOV AX, @DATA                ; initialize DS  
     MOV DS, AX

     LEA DX, PROMPT_1             ; load and display PROMPT_1  
     MOV AH, 9
     INT 21H

     CALL READ_BINARY_NUMBER      ; call the procedure READ_BINARY_NUMBER       

     CALL NEXT_LINE               ; call the procedure NEXT_LINE

     LEA DX, PROMPT_2             ; load and display PROMPT_2  
     MOV AH, 9
     INT 21H

     CALL DISPLAY_BINARY_NUMBER   ; call the procedure DISPLAY_BINARY_NUMBER         

     CALL NEXT_LINE               ; call the procedure NEXT_LINE

     LEA DX, PROMPT_3             ; load and display PROMPT_3
     MOV AH, 9
     INT 21H

     CALL REVERSE_BIT_PATTERN     ; call the procedure REVERSE_BIT_PATTERN

     CALL DISPLAY_BINARY_NUMBER   ; call the procedure DISPLAY_BINARY_NUMBER

     MOV AH, 4CH                  ; return control to DOS
     INT 21H
   MAIN ENDP



 ;------------------------  PROCEDURE DEFINITIONS  -------------------------;




 ;-----------------------------  NEXT_LINE  --------------------------------;


 NEXT_LINE PROC
   ; this procedure will move the cursor to the next line
   ; input : none
   ; output : none
   ; uses : MAIN

   PUSH AX                        ; push AX onto the STACK
   PUSH DX                        ; push DX onto the STACK

   MOV AH, 2                      ; set output function
   MOV DL, 0DH                    ; carriage return
   INT 21H                        

   MOV DL, 0AH                    ; line feed
   INT 21H

   POP DX                         ; pop a value from the STACK to DX
   POP AX                         ; pop a value from the STACK to AX

   RET                            ; return control to the calling procedure
 NEXT_LINE ENDP


 ;--------------------------  READ_BINARY_NUMBER  --------------------------;


 READ_BINARY_NUMBER PROC
   ; this procedure will read a number in binary form    
   ; input : none
   ; output : store binary number in BX
   ; uses : MAIN

   MOV CX, 16                     ; initialize loop counter
   XOR BX, BX                     ; clear BX
   MOV AH, 1                      ; set input function

   @LOOP_1:                       ; loop label
     INT 21H                      ; read a digit

     CMP AL, 0DH                  ; compare input and CR
     JE @END                      ; jump to label @END if input is CR
     AND AL, 0FH                  ; convert ascii to decimal code
     SHL BX, 1                    ; shift BX by 1 position towards left
     OR  BL, AL                   ; place the input decimal digit in BL
   LOOP @LOOP_1                   ; jump to label @LOOP_1 if CX!=0

   @END:                          ; jump label

   RET                            ; return control to the calling procedure
 READ_BINARY_NUMBER ENDP


 ;------------------------  DISPLAY_BINARY_NUMBER  -------------------------;


 DISPLAY_BINARY_NUMBER PROC
   ; this procedure will display a number in binary form    
   ; input : BX  
   ; output : none                       
   ; uses : MAIN

   PUSH BX                        ; push BX onto the STACK 

   MOV CX, 16                     ; initialize loop counter
   MOV AH, 2                      ; set output function

   @LOOP_2:                       ; loop label
     SHL BX, 1                    ; shift BX by 1 position towards left
     JC @ONE                      ; jump to label @ONE if CF=1
     MOV DL, 30H                  ; move 0 to DL
     JMP @DISPLAY                 ; jump tp label @DISPLAY

     @ONE:                        ; jump label
       MOV DL, 31H                ; move 1 to DL

     @DISPLAY:                    ; jump label
       INT 21H                    ; display a digit 
   LOOP @LOOP_2                   ; jump to label @LOOP_2 if CX!=0

   POP BX                         ; pop a value from STACK to BX

   RET                            ; return control to the calling procedure
 DISPLAY_BINARY_NUMBER ENDP 


 ;-------------------------  REVERSE_BIT_PATTERN  --------------------------;


 REVERSE_BIT_PATTERN PROC
   ; this procedure will read a number in binary form    
   ; input : BX  
   ; output : store the binary number in BX with reverse bit pattern
   ; uses : MAIN

   PUSH DX                        ; push DX onto the STACK

   MOV CX, 16                     ; initialize loop counter
   MOV DX, BX                     ; copy BX into DX
   XOR BX, BX                     ; clear BX

   @LOOP_3:                       ; loop label
     SHL BX, 1                    ; shift BX towards left by 1 position
     SHR DX, 1                    ; shift DX towards right by 1 position
     JNC @ZERO                    ; jump to label @ZERO if CF=0
     OR BX, 1                     ; set the LSb of BX

     @ZERO:                       ; jump label
       OR BX, 0                   ; set the LSB
   LOOP @LOOP_3                   ; jump to label @LOOP_3 if CX!=0

   POP DX                         ; pop a value from the STACK to DX

   RET                            ; return control to the calling procedure
 REVERSE_BIT_PATTERN ENDP





 END MAIN

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