Changing Text Colour with NASM Assembly

Expand Post »

Does anyone know how to change the colour of strings using x86 NASM Assembler? I've found tutorials like this:

Assembly Syntax (Toggle Plain Text)
mov  ah,  09h 
mov  al,  97 
mov  bx,  100b
mov  cx,  01h 
int  10h
mov  ah,  09h 
mov  al,  97 
mov  bx,  100b
mov  cx,  01h 
int  10h

Which prints the letter "A" once in the colour you choose. This is a handy tutorial, but I would like to be able to print the entire screen text (i.e more than one string) in the same colour. Anyone have any ideas?

Last edited by MichaelSammels; Oct 12th, 2009 at 8:01 am.

Similar Threads

using nasm in ubuntu in Assembly
What Editors Create This Code? in HTML and CSS
changing text in vb.net2003 in VB.NET
Changing text-size ??? in JavaScript / DHTML / AJAX
Change text colour in console in C++

MichaelSammels

Reputation Points: 10

Solved Threads: 0

Light Poster

Offline

36 posts
since Nov 2008

Permalink

Oct 13th, 2009

Re: Changing Text Colour with NASM Assembly

Color text-mode memory lies at segment 0xb800 and is 4000 bytes
in length 80*25*2 cuz each visible character on the screen
is accompanied by a text attribute byte.
00000000 Text Attribute Byte
XXBGxxFG
The low-nibble defines the foreground and the high-nibble
the background, and there is a way to disable the blink
bit.

Function 9 - Output Char And Attribute At Hardware Cursor
CX-Repeat
BH-Display Page
BL-Attribute
AL-Character
AH-9
INT 0x10

To clear the screen to one f/b color try this code:

Assembly Syntax (Toggle Plain Text)
clrscr:
mov dx, 0 ; Set cursor to top left-most corner of screen
mov bh, 0
mov ah, 0x2
int 0x10
mov cx, 2000 ; print 2000 chars
mov bh, 0
mov bl, 0x21 ; green bg/blue fg
mov al, 0x20 ; blank char
mov ah, 0x9
int 0x10
ret
clrscr:
mov dx, 0 ; Set cursor to top left-most corner of screen
mov bh, 0
mov ah, 0x2
int 0x10
mov cx, 2000 ; print 2000 chars
mov bh, 0
mov bl, 0x21 ; green bg/blue fg
mov al, 0x20 ; blank char
mov ah, 0x9
int 0x10
ret

This code writes a blue 'A' char to 0,0:

Assembly Syntax (Toggle Plain Text)
mov cx, 0xb800
mov es, cx
mov ax, 0x141
mov [es:0], ax
waitkey:
mov ah, 0x6
mov dl, 0xff
int 0x21
jz waitkey
ret
mov cx, 0xb800
mov es, cx
mov ax, 0x141
mov [es:0], ax
waitkey:
mov ah, 0x6
mov dl, 0xff
int 0x21
jz waitkey
ret

NotNull

Reputation Points: 36

Solved Threads: 19

Junior Poster

Offline

198 posts
since Oct 2008

This thread is solved

Either the thread starter or a moderator has marked this thread as solved. You can most likely trust the responses and answers given. There is most likely no reason for any further responses to be posted here. If you have a related question, please start a new thread in this forum instead.

This thread is more than three months old

No one has posted to this discussion for at least three months. Please let old threads die and do not reply to them unless you feel you have something new and valuable to contribute that absolutely must be added to make the discussion complete. Otherwise, please start a new thread in this forum instead.

Previous Thread in Assembly Forum Timeline: total rookie,pls help me

Next Thread in Assembly Forum Timeline: Array input question in assembly

DaniWeb Message

Cancel Changes

User Name
Password