Assembly text colors

Question

I\'m doing an iso file in assembly and I want to add color to the text (in this case: red).
Does anyone know how to do it?

[BITS 16]
[ORG 0x7C00]

jmp ma         


        

Answer 1

You can use Int 10/AH:0x09. It has the same arguments as Int 10/AH:0x0E, except that BH is the text color. Simply add the following line to your code.

mov ah, 09h
mov bh, 0xF0     ; add this line, this is the text color (white on black)
int 10h

Another alternative that I use, since BIOS functions, aren't available in protected mode. Using the memory at 0x0B800. The general code then becomes:

mov ebx, 0xb800      ; the address for video memeory
mov ah, 0xF0         ; the color byte is stored in the upper part of ax (ah).
printstr:
  lodsb              ; load char at si into al and increment si.
  cmp al, 0
  je .done
  mov [ebx], ax      ; move the character into video memeory.
  add ebx, 2         ; move the video memeory pointer up two bytes.
  jmp printstr
.done:
  ret

Additional resources for looking into this may include:

• Editing Video Memory Directly.
• Source code for Example OS using these methods.
• Int 10h/AH:0x09