'Change border at nasm

I'm using NASM (assembly x86) at REAL mode and i'm trying to change my border color, i've great success changing all background but my objective is to change only the border of one line (cursor line).

How can I do this?

assemblyx86dosnasm


Solution 1:[1]

You'll need to change the background color when the electron beam is at the first raster line of the cursor line, and change it back when it has reached the last raster line of the cursor line. To do this you need to calculate which raster line corresponds to your chosen cursor line, and know how to ask the video card for the current raster line.

Solution 2:[2]

> You can use this script to set the border color in NASM (Assembly)

org 100h

jmp start
clrscr:     
    push es
    push ax
    push di

    mov  ax, 0xb800
    mov  es, ax
    mov  di, 0

    nextloc:
        mov  word [es:di], 0x0720
        add  di, 2
        cmp  di, 4000
        jne  nextloc

    pop  di 
    pop  ax
    pop  es
    ret
setBorderColor:
;// Left side column
    MOV AH, 06h    ; Scroll up function
    XOR AL, AL     ; number of lines by which to scroll up (00h = clear entire window)
    XOR CX, CX     ; Upper left corner CH=row, CL=column
    MOV DX, 3501H  ; lower right corner DH=row, DL=column 
    MOV BH, 1Eh    ; YellowOnBlue
    INT 10H
;// Right side column
    MOV AH, 06h    ; Scroll down function
    XOR AL, AL     ; number of lines by which to scroll up (00h = clear entire window)
    ;XOR CX, CX     ; Upper left corner CH=row, CL=column
    mov ch, 00
    mov cl, 78
    MOV DX, 2475H  ; lower right corner DH=row, DL=column 
    MOV BH, 1Eh    ; YellowOnBlue
    INT 10H
;// Top Row
    MOV AH, 06h    ; Scroll down function
    XOR AL, AL     ; number of lines by which to scroll up (00h = clear entire window)
    ;XOR CX, CX     ; Upper left corner CH=row, CL=column
    mov ch, 00h
    mov cl, 00h
    MOV DX, 0179H  ; lower right corner DH=row, DL=column 
    MOV BH, 1Eh    ; YellowOnBlue
    INT 10H
    mov  ah, 00h      ; BIOS.WaitKeyboardKey
    int  16h          ; -> AX

;// Bottom Row
    MOV AH, 06h    ; Scroll down function
    XOR AL, AL     ; number of lines by which to scroll up (00h = clear entire window)
    ;XOR CX, CX     ; Upper left corner CH=row, CL=column
    mov ch, 18h ; 24= 18 hex
    mov cl, 00h 
    MOV DX, 1879H  ; lower right corner DH=row, DL=column 
    MOV BH, 1Eh    ; YellowOnBlue
    INT 10H
    mov  ah, 00h      ; BIOS.WaitKeyboardKey
    int  16h          ; -> AX
ret

start: 
call clrscr
call setBorderColor 
mov ax, 0x4c00 ; terminate program
int 0x21

Output

enter image description here

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 Jens Björnhager
Solution 2 Engr. Khuram Shahzad

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