name "hi-world"

; this example prints out  "hello world!" 
; by writing directly to video memory. 
; in vga memory: first byte is ascii character, byte that follows is character attribute. 
; if you change the second byte, you can change the color of 
; the character even after it is printed. 
; character attribute is 8 bit value, 
; high 4 bits set background color and low 4 bits set foreground color. 

; hex    bin        color 
;  
; 0      0000      black 
; 1      0001      blue 
; 2      0010      green 
; 3      0011      cyan 
; 4      0100      red 
; 5      0101      magenta 
; 6      0110      brown 
; 7      0111      light gray 
; 8      1000      dark gray 
; 9      1001      light blue 
; a      1010      light green 
; b      1011      light cyan 
; c      1100      light red 
; d      1101      light magenta 
; e      1110      yellow 
; f      1111      white 



org 100h

; set video mode     
mov ax, 3     ; text mode 80x25, 16 colors, 8 pages (ah=0, al=3) 
int 10h       ; do it! 

; cancel blinking and enable all 16 colors: 
mov ax, 1003h
mov bx, 0
int 10h


; set segment register: 
mov     ax, 0b800h
mov     ds, ax

; print "hello world" 
; first byte is ascii code, second byte is color code. 

mov [02h], 'h'

mov [04h], 'e'

mov [06h], 'l'

mov [08h], 'l'

mov [0ah], 'o'

mov [0ch], ','

mov [0eh], 'w'

mov [10h], 'o'

mov [12h], 'r'

mov [14h], 'l'

mov [16h], 'd'

mov [18h], '!'




; color all characters: 
mov cx, 12  ; number of characters. 
mov di, 03h ; start from byte after 'h' 

c:  mov [di], 11101100b   ; light red(1100) on yellow(1110) 
    add di, 2 ; skip over next ascii code in vga memory. 
    loop c

; wait for any key press: 
mov ah, 0
int 16h

ret