Prints diamond on console taking user input. Don't input 0 or 1 otherwise fix code yourself.

8086 asm diamond print using user input.asm

;Author:quickgrid
;Site:  http://quickgrid.blogspot.com
;Code:  8086 assembly diamond print dual loop explained code


org 100h
.stack 100h

.data
           
    ;variable definitions
           
    i db ?
    j db ?
    k db ?
           
    num     db '1'    
    counter db  1    
    input   db  ?
    
    counter2 db ?
     
    
.code
.startup
    
    ;take input
    mov ah, 1
    int 21h
    mov j, al    
    
    ;save the input in a variable    
    mov input, al
    
    ;print new line
    mov ah, 2
    mov dl, 0dh
    int 21h
    mov dl, 0ah
    int 21h 
    
    ;upper triangle loop                  
    upper_triangle_loop:
        
        ;move current outer loop counter to i
        mov bl, j
        mov i, bl
            
        ;skip printing space in the last loop                             
        cmp i, '1'
        je skip_space_loop
                        
        ;loop and print space
        space_loop:
            
            mov dl, ' '
            mov ah, 2
            int 21h
            
            dec i
            cmp i, '1'
            jne space_loop
        
        skip_space_loop:
        
        ;reset loop counter to print more numbers              
        mov bl, counter
        mov k, bl
                          
        ;print output numbers in loop                  
        number_print_loop:
            
            ;check if even or odd
            mov al, num
            mov bl, 2
            div al
                                 
            ;print space if in even positions
            cmp al, 0
            je print_space
            
            ; print number
            mov dl, num
            mov ah, 2
            int 21h

            ;if number printing skipped then print space
            print_space:
                    
                mov dl, ' '
                mov ah, 2
                int 21h
                    
            ;exit loop if loop counter is zero
            dec k
            cmp k, 0
            jg number_print_loop 
        
        ;increment counter to print two more numbers than previous    
        add counter, 1        
        inc num
        
        ;print new line
        mov ah, 2
        mov dl, 0dh
        int 21h
        mov dl, 0ah
        int 21h
        
    dec j
    cmp j, '0'
    jne upper_triangle_loop
    
    
    ;reset all previously used variables
    mov bl, input
    mov j, bl                                    
                                        
    mov bl, 1
    mov counter, bl
    
    dec num                      
     
    ;loop twice the size of previous value minus one
    mov bl, input
    sub bl, 30h
    mov counter2, bl 
    
    ;print the lower triangle
    lower_triangle_loop:
                       
        ;replaces i with new counter value            
        mov bl, counter
        mov i, bl
                                       
        ;print spaces
        space_loop2:
             
            
            mov dl, ' '
            mov ah, 2
            int 21h
             
        dec i
        cmp i, 0
        jne space_loop2 
        
        
        ;increment counter to print one more space than previous
        inc counter
        
        
        mov bl, counter2
        mov k, bl
        
        dec num
        
        
        ;print the numbers
        number_print_loop2:
        
            mov al, num
            mov bl, 2
            div al
            
            cmp al, 0
            je print_space2
            
            mov ah, 2
            mov dl, num
            int 21h
            
            print_space2:            
                
                mov ah, 2
                mov dl, ' '
                int 21h
                
        dec k
        cmp k, 1
        jne number_print_loop2
        
        dec counter2
        
        ;print new line
        mov ah, 2
        mov dl, 0dh
        int 21h
        mov dl, 0ah
        int 21h
        
        
    dec j
    cmp j, '1'    
    jne lower_triangle_loop
           
           
    ;print new line
    mov ah, 2
    mov dl, 0dh
    int 21h
    mov dl, 0ah
    int 21h
    
.exit