Note: this assignment from microprocessor and Interface Course.

1) addition and substraction 2+3-1=4 2) Reverse String

1 input string and output:

; Displaying a string

include 'emu8086.inc' ; you have to write this line

PRINTN 'Enter length of string' mov ah,1h int 21h

; int 21h means, call the interrupt handler 0x21 which is the DOS Function dispatcher. ; the \"mov ah,01h\" is seeting AH with 0x01, which is the Keyboard Input with Echo handler ; in the interrupt printn print \"Enter String here: \" mov cl,al sub cl,'0' ; substract instruction mov dl,cl ; mov means move the content of cl registor to dl mov bx,0 p1: mov ah,1h int 21h ; again input mov [bx],ax ; doing a loop by transfering [x+bx] element to ax inc bx ; incrementing bx regitor dec cl cmp cl,0 ; comparing jne p1 ; jump not equal. jump to instruction p1 printn PRINT 'inputted string : ' mov cl,dl mov bx,0

output: mov dl,[bx] mov ah,2h int 21h inc bx dec cl cmp cl,0 jne output printn mov ax, 4c00h ; return to ms-dos // essential line int 21h

ret