8086 program to Add two 16 bit numbers

03:49


ØØ       Explanation :
·            Consider that a word of data is present in the AX register and a 2nd word of data is present in the BX register.
·            We have to add word in AX with the word in BX. Using ADD instruction, add the contents.
·            Result will be stored in the AX register. Display the result using display routine.



For example :
AX = 1234 H

1234 H

BX = 0100 H
+
0100 H



1334 H
ØØ       Algorithm :
Step I       :    Initialise the data segment.
Step II     :    Get the first number in AX register.
Step III   :    Get the second number in BX register.
Step IV    :    Add the two numbers.
Step V     :    Display the result.
Step VI    :    Stop
ØØ       Flowchart : Refer flowchart

ØØ       Program :
.model small
.data
a dw 1234H
b dw 0100H
.code
       mov     ax, @data      ; Initialize data section
       mov     ds, ax
       mov     ax, a             ; Load number1 in ax
       mov     bx, b            ; Load number2 in bx
       add      ax, bx           ; add numbers. Result in ax
       mov     ch, 04h         ; Count of digits to be displayed
       mov     cl, 04h ; Count to roll by 4 bits
       mov     bx, ax           ; Result in reg bh
l2:    rol       bx, cl            ; roll bl so that msb comes to lsb
       mov     dl, bl            ; load dl with data to be displayed
       and      dl, 0fH ; get only lsb
       cmp     dl, 09           ; check if digit is 0-9 or letter A-F
       jbe       l4
       add      dl, 07           ; if letter add 37H else only add 30H
l4:    add      dl, 30H
       mov     ah, 02           ; Function 2 under INT 21H (Display character)
       int       21H
       dec      ch                ; Decrement Count
       jnz       l2
       mov     ah, 4cH         ; Terminate Program
       int       21H
end
ØØ       Result :
C:\programs>tasm 16-add.asm
Turbo Assembler  Version 3.0  Copyright (c) 1988, 1991 Borland International
Assembling file:   16-add.asm
Error messages:    None
Warning messages:  None
Passes:            1
Remaining memory:  438k
C:\programs>tlink 16-add
Turbo Link  Version 3.0 Copyright (c) 1987, 1990 Borland International
Warning: No stack
C:\programs>16-add
1334