.model small .stack 400h .data

message db "hello. ", 0ah, 0dh, "$" firstdigit db ? seconddigit db ? thirddigit db ? number dw ? newnumber db ? anumber dw 0d bnumber dw 0d Firstn db 0ah, 0dh, "Enter first 3 digit number: ","$" secondn db 0ah, 0dh, "Enter second 3 digit number: ","$" messageB db 0ah, 0dh, "HCF of two number is: ","$" linebreaker db 0ah, 0dh, ' ', 0ah, 0dh, '$'

.code

Start: mov ax, @data ; establish access to the data segment mov ds, ax ; mov number, 0d

mov dx, offset message ; print the string "yob choi 0648293" mov ah, 9h
int 21h

num: mov dx, offset Firstn ; print the string "put 1st 3 digit" mov ah, 9h
int 21h ;run JMP FirstFirst ; jump to FirstFirst

FirstFirst: ;first digit
mov ah, 1d ;bios code for read a keystroke int 21h ;call bios, it is understood that the ascii code will be returned in al mov firstdigit, al ;may as well save a copy sub al, 30h ;Convert code to an actual integer cbw ;CONVERT BYTE TO WORD. This takes whatever number is in al and ;extends it to ax, doubling its size from 8 bits to 16 bits ;The first digit now occupies all of ax as an integer mov cx, 100d ;This is so we can calculate 100*1st digit +10*2nd digit + 3rd digit mul cx ;start to accumulate the 3 digit number in the variable imul cx ;it is understood that the other operand is ax ; the result will use both dx::ax ;dx will contain only leading zeros add anumber, ax ;save

;Second Digit
mov ah, 1d ;bios code for read a keystroke int 21h ;call bios, it is understood that the ascii code will be returned in al mov seconddigit, al ;may as well save a copy sub al, 30h ;Convert code to an actual integer cbw ;CONVERT BYTE TO WORD. This takes whatever number is in al and ;extends it to ax, boubling its size from 8 bits to 16 bits ;The first digit now occupies all of ax as an integer mov cx, 10d ;continue to accumulate the 3 digit number in the variable mul cx ;it is understood that the other operand is ax, containing first digit ;the result will use both dx::ax ;dx will contain only leading zeros. add anumber, ax ;save

;third Digit mov ah, 1d ;samething as above int 21h ; mov thirddigit, al ; sub al, 30h ; cbw ;

add anumber, ax ; jmp num2 ;go to checks

Num2: mov dx, offset secondn ; print the string "put 2nd 3 digits" mov ah, 9h
int 21h ;run JMP SecondSecond

SecondSecond:

;first digit
mov ah, 1d ;bios code for read a keystroke int 21h ;call bios, it is understood that the ascii code will be returned in al mov firstdigit, al ;may as well save a copy sub al, 30h ;Convert code to an actual integer cbw ;CONVERT BYTE TO WORD. This takes whatever number is in al and ;extends it to ax, doubling its size from 8 bits to 16 bits ;The first digit now occupies all of ax as an integer mov cx, 100d ;This is so we can calculate 100*1st digit +10*2nd digit + 3rd digit mul cx ;start to accumulate the 3 digit number in the variable imul cx ;it is understood that the other operand is ax ; the result will use both dx::ax ;dx will contain only leading zeros add bnumber, ax ;save

;Second Digit
mov ah, 1d ;bios code for read a keystroke int 21h ;call bios, it is understood that the ascii code will be returned in al mov seconddigit, al ;may as well save a copy sub al, 30h ;Convert code to an actual integer cbw ;CONVERT BYTE TO WORD. This takes whatever number is in al and ;extends it to ax, boubling its size from 8 bits to 16 bits ;The first digit now occupies all of ax as an integer mov cx, 10d ;continue to accumulate the 3 digit number in the variable mul cx ;it is understood that the other operand is ax, containing first digit ;the result will use both dx::ax ;dx will contain only leading zeros. add bnumber, ax ;save

;third Digit mov ah, 1d ;samething as above int 21h ; mov thirddigit, al ; sub al, 30h ; cbw ;

add bnumber, ax ; jmp compare ;go to compare

compare:

CMP ax, anumber ;comparing numbB and Number JA comp1 ;go to comp1 if anumber is bigger CMP ax, anumber ; JB comp2 ;go to comp2 if anumber is smaller CMP ax, anumber ; JE equal ;go to equal if two numbers are the same JMP compare ;go to compare (avioding error)

comp1:

SUB ax, anumber; subtract smaller number from bigger number JMP compare ;

comp2: SUB anumber, ax; subtract smaller number from bigger number JMP compare ;

equal: mov ah, 9d ;make linkbreak after the 2nd 3 digit number mov dx, offset linebreaker int 21h mov ah, 9d ;print "HCF of two number is:" mov dx, offset messageB int 21h

mov ax,anumber ;copying 2nd number into ax
add al,30h ; converting to ascii
mov newnumber,al ; copying from low part of register into newnumb

mov ah, 2d ;bios code for print a character mov dl, newnumber ;we had saved the ascii code here int 21h ;call to bios

JMP exit;

exit:

mov ah, 4ch
int 21h ;exit the program

End

hi, this is a program that finds highest common factor of 2 different 3digit number. if i put 200, 235,312 (low numbers) it works fine. but if i put 500, 550, 654(bigger number) the program crashes after the 2nd 3digit number is entered. can you help me to find out what problem is?