8086 program to Add two 16 bit numbers

ØØ       Explanation :

·            Consider that a word of data is present in the AX register and a 2^nd 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