Change background color of string

Question

I have a problem in NASM. I want to change the background colour, but only for one string.

These are my macros:

%macro SetBackGroundColour 0
    mov dx, 0
    mov bh, 0
    mov ah, 0x2
    int 0x10
    mov cx, 2000 
    mov bh, 0
    mov bl, 0x21 
    mov al, 0x20 
    mov ah, 0x9
    int 0x10     
%endmacro

%macro printOnTheScreen 1
    xor dx,dx 
    mov ah, 09h 
    mov dx, %1 
    int 21h 
    xor dx, dx
%endmacro

I tried other changes, but nothing worked.

Specifying the exact asm flavor you are using would help others spot your question (and possibly answer it) much quicker. — D-side, Apr 28 '15 at 16:38
http://stackoverflow.com/questions/29460318/how-to-print-colored-string-in-assembly-language/29478158#29478158 — Jose Manuel Abarca Rodríguez, Apr 28 '15 at 16:43
http://stackoverflow.com/questions/29704807/the-following-codes-should-print-jan-string-in-video-mode-but-it-prints-some-sym/29705041#29705041 — Jose Manuel Abarca Rodríguez, Apr 28 '15 at 16:45
thanks, but I don't want to change colour of a string, but background colour of the string. — Ola214, Apr 28 '15 at 16:50
I mean I don't want all the background being green as I had written in a macro, but only when there is a string — Ola214, Apr 28 '15 at 16:51
The given links allow you to display a string with some color, ONLY the string will have color. Try the interrupts and their parameters. — Jose Manuel Abarca Rodríguez, Apr 28 '15 at 16:53
I wanted to do that. but I don't have 15 reputation, so I unfortunately I can't :( mov ah, 9 mov bh, 0 mov bl, 0x20 ;ANY COLOR. mov cx, 5 ;HOW MANY TIMES TO DISPLAY CHAR. int 10h what do ah and bh? — Ola214, Apr 28 '15 at 17:08
Loop through the characters of the string. Display each char with the desired color. What answer or technique are you using? — Jose Manuel Abarca Rodríguez, Apr 28 '15 at 17:18
Ok, thank you, I asked you, because I want my string in right corner and I wonder if it works only for the beginning of the line. — Ola214, Apr 28 '15 at 17:22
It depends on the technique. Are you using interrupt 10h ah 13h, or B800h? — Jose Manuel Abarca Rodríguez, Apr 28 '15 at 17:23
Oh ok, now I understand youre question :) I use interrupt 10h. Sorry, I'm begginer — Ola214, Apr 28 '15 at 17:25
The interrupt accepts the X,Y position in DL,DH = http://stackoverflow.com/questions/29460318/how-to-print-colored-string-in-assembly-language/29478158#29478158 , where the comments say "x (screen coordinate)". — Jose Manuel Abarca Rodríguez, Apr 28 '15 at 17:29
%macro moveString 2 mov ah,02H mov bh, 0 mov dh, %1 ;number of x mov dl, %2 ;number of y int 21h %endmacro but it doesn't work — Ola214, Apr 28 '15 at 17:31
Is it possible to replace (just to test) the %1 and %2 with numbers? — Jose Manuel Abarca Rodríguez, Apr 28 '15 at 17:33
What if, instead of a macro, you create a PROCEDURE? Does it got to be a macro? — Jose Manuel Abarca Rodríguez, Apr 28 '15 at 17:40
No, it doesn't. It only has to work :D I have never used procedure, so I would try. Will procedure uses parameters like macro does ? Because in your code you don't use parameters or I don't see that. Because I have to change places of a string for some times. — Ola214, Apr 28 '15 at 17:41
http://wklej.org/id/1699002/ I have error :parser:instruction expected when I compile :( — Ola214, Apr 28 '15 at 17:50
What is the instruction that gives you the error? Add RET before the end of the PROC. — Jose Manuel Abarca Rodríguez, Apr 28 '15 at 17:51
ah=02h with int 21h requires the character to display in DL. Move some char to DL. And it uses the current cursor position. Do GOTOXY before. — Jose Manuel Abarca Rodríguez, Apr 28 '15 at 17:55

Jose Manuel Abarca Rodríguez · Answer 1 · 2015-04-28T20:47:57.167

Next is a procedure in (almost) NASM to display string with color, notice how parameters are set before the CALL :

SECTION .data

text:  db  "Just some text"  ;LENGTH = 14.
color: db 181          
x:     db 0
y:     db 0

SECTION .text

global main
main:

  mov  bp, text ;STRING TO DISPLAY.
  mov  cx, 14          ;STRING LENGTH.
  mov  [x], byte 50    
  mov  [y], byte 20
  call color_string

;FINISH PROGRAM.
  mov  ax,4c00h
  int  21h

;----------------------------------------------     
;PARAMETERS : BP = OFFSET OF STRING TO DISPLAY.  
;             CX = STRING LENGTH.
;             COLOR = VARIABLE WITH COLOR (0..255).
;             X,Y   = VARIABLES WITH COORDINATES.

color_string:

  mov  ax, ds
  mov  es, ax         ;ES SEGMENT MUST POINT TO DATA SEGMENT.
  mov  ah, 13h        ;SERVICE TO DISPLAY STRING WITH COLOR.
  mov  bh, 0          ;PAGE (ALWAYS ZERO).
  mov  bl, color
  mov  dl, x          ;X (SCREEN COORDINATE). 
  mov  dh, y          ;Y (SCREEN COORDINATE). 
  int  10h           ;BIOS SCREEN SERVICES.  

  ret

The code to set cursor position is this :

mov  ah, 2  ;SERVICE TO SET CURSOR POSITION.
mov  bh, 0  ;PAGE NUMBER (ALWAYS ZERO).
mov  dl, x  ;X COORDINATE 0..79.
mov  dh, y  ;Y COORDINATE 0..24.
int  10h    ;BIOS VIDEO SERVICES.

I tried running your program but it says ld: warning: cannot find entry symbol _start; defaulting to 0000000008048080` any issue here — varad, Apr 02 '18 at 11:49
@aryan, try this ► https://stackoverflow.com/questions/34758769/load-warning-cannot-find-entry-symbol-start — Jose Manuel Abarca Rodríguez, Apr 02 '18 at 13:55

Change background color of string

1 Answers1