multiplying two two digit numbers with both the numbers taken as input and result is also to be printed in Tasm

Question

i am not understanding as to what can be done in this case single digit multiplication was possible using the AAM instruction however for AAM you need unpacked BCD therefore the result after two digit multiplication wont be accumulated in the AX register...

so i need an idea as to how i can proceed with this problem .thank you

here is how the input should look like (to take one two digit number) and BCD is desirable

mov dx,offset msg
mov ah,09h
int 21h

mov ah,01h
int 21h

mov ch,al
sub ch,30h
ror ch,04h

mov ah,01h
int 21h

mov cl,al
sub cl,30h
add cl,ch

Answer 1

mynumber1 db ?
mynumber2 db ?

mov ah,01h
int 21h
sub al, 30h <- ASCII to value 

mov bl, 0Ah 
mul bl <- multiply al with 10

mov mynumber1, al <- mynumber1 now stores the tens (i.e. if you entered 8 it's now 80)

mov ah,01h
int 21h 
sub al, 30h <- ASCII to value, al now stores the ones

add mynumber1, al <- now your two-digit number is completely in mynumber1

Now repeat the same for mynumber2. Then:

mov al, mynumber1
mov bl, mynumber2

mul bl

Now the product is in AX. Proceed by converting the content of AX back to BCD, if you really need to.

---

The following code will print a number with up to 4 digits stored in AX:

xor dx,dx
mov bx,03E8h
div bx
call printdig

mov ax,dx
xor dx,dx
mov bx,0064h
div bx
call printdig

mov ax,dx
xor dx,dx
mov bx,000Ah
div bx
call printdig

;remainder from last div still in dx
mov al,dl
call printdig

Note that you need the following helper function, which prints a single digit from al:

printdig proc
push dx
mov dl,al
add dl,30h
mov ah,02h
int 21h
pop dx
ret
printdig endp

Answer 2

Multiplication of 2 digit number in assembly language, using BCD instructions like aam (ASCII adjust AX After Multiply) to work with the numbers in decimal, one decimal digit per byte.

(The other way would be to convert the 2-digit inputs to a one-byte binary integer each, and do a standard mul, then convert the result in AX back to a string like in Displaying numbers with DOS)

org 100h

.data      
num1_O db ?
num2_O db ?
num1_T db ?
num2_T db ? 
temp db ? 
carry db ? 
1st db ?
2nd db ?
3rd db ?
4th db ?
ent_num db " ENTER NUMBER $"
ans db "mul of both number is = $"

.code
start:                          
     mov ax, @data
     mov ds, ax
     mov dx, offset ent_num
     mov ah, 09h
     int 21h
     
     mov ah, 01h               ;1
     int 21h   
     sub al, 30h
     mov num1_T, al
     
     mov ah, 01h               ;2
     int 21h   
     sub al, 30h
     mov num1_O, al  
     
     
     mov dx, offset ent_num
     mov ah, 09h
     int 21h  
     
     mov ah, 01h                 ;1
     int 21h
     sub al, 30h
     mov num2_T, al
     
     mov ah, 01h                  ;2       al
     int 21h
     sub al, 30h 
     mov num2_O, al 
     
     mov 1st, 0
     mov 2nd, 0
     mov 3rd, 0
     mov 4th, 0
     
     
     
     mov al, num2_O
     mul num1_O
     mov ah, 00h
     aam
     
     add 3rd, ah         ;1st carry            4th solved
     add 4th, al 
     
     
     mov al, num2_O
     mul num1_T
     mov ah, 00h
     aam
     
     add 2nd, ah            ;carry
     add 3rd, al  
                    
     
     mov al, num2_T
     mul num1_O
     mov ah, 00h
     aam
     
     add 2nd, ah            ;carry
     add 3rd, al   
     
     
     mov al, num2_T
     mul num1_T
     mov ah, 00h
     aam
     
     add 1st, ah            ;carry
     add 2nd, al   
     
     mov dl, 010
     mov ah, 02h
     int 21h
     mov dx, offset ans
     mov ah, 09h
     int 21h
     
     
     mov al, 3rd
     mov ah, 00h
     aam
     
     add 2nd, ah
     mov 3rd, al 
     
     
     mov al, 2nd
     mov ah, 00h
     aam
     
     mov 2nd, al
     add 1st, ah
     
     mov dl, 1st
     add dl, 30h
     mov ah, 02h
     int 21h 
     
     mov dl, 2nd
     add dl, 30h
     mov ah, 02h
     int 21h
     
     mov dl, 3rd
     add dl, 30h
     mov ah, 02h
     int 21h
     
     mov dl, 4th
     add dl, 30h
     mov ah, 02h
     int 21h
     end start
   

ret