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assemblyx86dosmasmirvine16

Write character to video buffer MASM


I am trying to write the letter 'D' in blue on a white background by moving it to the video buffer. What is wrong with this code?

INCLUDE Irvine16.inc

.code
main PROC

mov ax,@data
mov ds,ax

mov si, 0b800h
mov word ptr [si], 44h
mov word ptr [si+2] 0701h

mov ah, 08h
int 21h

exit

main ENDP

Made the changes to above. It now assembles, but displays nothing.


Solution

  • Sample example:

    name "hello-world"
    org 100h
    
    ; set video mode     
    mov ax, 3     ; text mode 80x25, 16 colors, 8 pages (ah=0, al=3) 
    int 10h       ; do it! 
    
    ; cancel blinking and enable all 16 colors: 
    mov ax, 1003h
    mov bx, 0
    int 10h
    
    
    ; set segment register: 
    mov     ax, 0b800h
    mov     ds, ax
    
    ; print "hello world" 
    ; first byte is ascii code, second byte is color code. 
    
    mov [02h], 'h'
    
    mov [04h], 'e'
    
    mov [06h], 'l'
    
    mov [08h], 'l'
    
    mov [0ah], 'o'
    
    mov [0ch], ','
    
    mov [0eh], 'w'
    
    mov [10h], 'o'
    
    mov [12h], 'r'
    
    mov [14h], 'l'
    
    mov [16h], 'd'
    
    mov [18h], '!'
    
    
    
    
    ; color all characters: 
    mov cx, 12  ; number of characters. 
    mov di, 03h ; start from byte after 'h' 
    
    c:  mov [di], 11101100b   ; light red(1100) on yellow(1110) 
        add di, 2 ; skip over next ascii code in vga memory. 
        loop c
    
    ; wait for any key press: 
    mov ah, 0
    int 16h
    
    ret
    

    Hope this sample helps you