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NASM Forum => Using NASM => Topic started by: nobody on June 12, 2007, 03:09:56 PM

Title: How can I change text color in linux?
Post by: nobody on June 12, 2007, 03:09:56 PM

Hello

How can I change text color or background color in linux? In windows it can be done in this way:
%macro screen 2
xor bh,bh
mov al,%1
mov ah,%2
shl ah,4
or bh,ah
or bh,al
mov ah,06h
xor al,al
xor ch,ch
xor cl,cl
mov dl,80
mov dh,40
int 10h
mov ah,02h
xor bh,bh
xor dh,dh
xor dl,dl
int 10h
%endmacro

Thanks

Title: Re: How can I change text color in linux?
Post by: nobody on June 12, 2007, 06:01:38 PM

Well, one way would be VT100 escape sequences...

http://www.termsys.demon.co.uk/vtansi.htm (http://www.termsys.demon.co.uk/vtansi.htm)

For example:

global _start

section .data

setcolor db 1Bh, '[36;40m', 0  ; cyan on black
    .len equ $ - setcolor

section .text
_start:
    mov eax, 4
    mov ebx, 1
    mov ecx, setcolor
    mov edx, setcolor.len
    int 80h

mov eax, 1
    xor ebx, ebx
    int 80h

Needless to say, you'll want a little more than this. (setting everything back to "normal" would be polite)

Another method would be to open /dev/vcsa0 (or some other number?). That will give you, after a short "header", a setup much like "direct screen write" from dos - character in even bytes, attribute in odd bytes.

I'm not aware of anything "like" the bios interrupts available in 16-bit code. I suspect the VT100 approach is your best bet.

Best,
Frank

Title: Re: How can I change text color in linux?
Post by: kavik on June 14, 2007, 08:53:10 AM

Hello

I have one more question.

When I try to create macros I getting error: "The NetwidSegmentation"

There is the code of macros:

%macro colour 2
 pushad
        pushf
 mov eax,4
        mov ebx,1
  jmp %%wr
%%setcolor db 1Bh,'[31;40m',0
%%wr: mov ecx,%%setcolor
 mov edx,%2
 int 80h
 ;mov eax,1
 ;mov ebx,0
 ;int 80h
  popf
        popad
%endmacro

Please, tell me what i am doing wrong
Thanks