assemblyx86-16tasmdosbox

How do i fix the equivalent value of this code? : Using tasm/tlink/dosbox in notepad++


I'll trying to code Bases, I'm trying to code using bases but when I encode there is a correct equivalent value appearing but there are more incorrect equivalents. What wrong in my code?

My code: Needs to type 2 digits and based on the required base range and the equivalent base will appear. If you notice that I don't have any comparing to find out if base 3 or the required base needs to be input, I'll put it next but first I have to think about what's wrong with the logic of my code.

My Code in notepad++:

.model small
.stack 100h
.data
    
    Spc     db 0dh,0ah, " $"                                                ;New Line
    
    ;Bases Conversion
    ConT    db 0dh,0ah, "   Conversion  $"                                  ;Conversion Title
    ConBs3  db 0dh,0ah, "Base 3  to Base 5  "                           
            db 0dh,0ah,0dh,0ah, "Base 3 [00 to 22] : $"                     ;Enter Base 03 Number
    EqBs3       db 0dh,0ah, "Base 5 Equivalent : $"                         ;Equivalent Base 05
    
    ConBs4  db 0dh,0ah, "Base 4  to Base 5  "                           
            db 0dh,0ah,0dh,0ah, "Base 4 [00 to 33] : $"                     ;Enter Base 04 Number
    EqBs4       db 0dh,0ah, "Base 5 Equivalent : $"                         ;Equivalent Base 05
    
    ConBs5  db 0dh,0ah, "Base 5  to Base 4  "                           
            db 0dh,0ah,0dh,0ah, "Base 5 [00 to 44] : $"                     ;Enter Base 05 Number
    EqBs5       db 0dh,0ah, "Base 4 Equivalent : $"                         ;Equivalent Base 04
    
.code
main proc
    
    mov ax,@data                    ;initialize ds
    mov ds,ax
    
    Base3:
        mov ah,09h
        lea dx, Spc                 ;new line
        int 21h
        
        lea dx, ConT
        int 21h
        lea dx, ConBs3
        int 21h
        
        mov ah,01h
        int 21h                     ;1st Digit
        
        sub al,30h
        mov ch,al
        
        mov ah,01h
        int 21h                     ;2nd Digit
        
        sub al,30h
        mov cl,03h
        mul cl
        mov bx,ax
    
    Con1:
        add ch,bl
        mov ax,0000h
        mov al,ch
        mov bh,05h
        div bh
        mov cx,ax
        add cx,3030h
        
        mov ah,09h
        lea dx, EqBs3
        int 21h
        
        mov ah,02
        mov dl,cl
        int 21h
        mov dl,ch
        int 21h
    
    Base4:
        mov ah,09h
        lea dx, Spc                 ;new line
        int 21h
        
        lea dx, ConBs4
        int 21h
        
        mov ah,01h
        int 21h                     ;1st Digit
        
        sub al,30h
        mov ch,al
        
        mov ah,01h
        int 21h                     ;2nd Digit
        
        sub al,30h
        mov cl,04h
        mul cl
        mov bx,ax
        
    Con2:
        add ch,bl
        mov ax,0000h
        mov al,ch
        mov bh,05h
        div bh
        mov cx,ax
        add cx,3030h
        
        mov ah,09h
        lea dx, EqBs4
        int 21h
        
        mov ah,02
        mov dl,cl
        int 21h
        mov dl,ch
        int 21h
        
    Base5:
        mov ah,09h
        lea dx, Spc                 ;new line
        int 21h
        
        lea dx, ConBs5
        int 21h
        
        mov ah,01h
        int 21h                     ;1st Digit
        
        sub al,30h
        mov ch,al
        
        mov ah,01h
        int 21h                     ;2nd Digit
        
        sub al,30h
        mov cl,05h
        mul cl
        mov bx,ax
        
    Con3:
        add ch,bl
        mov ax,0000h
        mov al,ch
        mov bh,04h
        div bh
        mov cx,ax
        add cx,3030h
        
        mov ah,09h
        lea dx, EqBs5
        int 21h
        
        mov ah,02
        mov dl,cl
        int 21h
        mov dl,ch
        int 21h
        
        
    mov ah,4Ch                      ;end here
    int 21h
    
main endp
end main

Equivalent Output Error:

enter image description here


Solution

  • Building the number is faulty

    mov ah,01h
    int 21h                     ;1st Digit
    sub al,30h
    mov ch,al
    
    mov ah,01h
    int 21h                     ;2nd Digit
    sub al,30h
    mov cl,03h
    mul cl
    mov bx,ax
    

    The first digit that you input it the Most Significant Digit and that is the digit that you need to multiply by the number base. Your code is erroneously multiplying the Least Significant Digit!

        mov ah, 01h
        int 21h        ; 1st Digit
        sub al, 30h
        mov cl, 3      ; Radix
        mul cl
        mov ch, al     ; -> CH = MostSignificantDigit * Radix
        
        mov ah, 01h
        int 21h        ; 2nd Digit
        sub al, 30h
        add ch, al     ; -> CH = MostSignificantDigit * Radix + LeastSignificantDigit
    

    Same for the other number bases too.