[BITS 16]
[ORG 0x7C00]

;Program that uses loops to print out a square as well as student details and favourite movie.


top:
    ;; Put 0 into ds (data segment)
    ;; Can't do it directly
    mov ax,0x0000
    mov ds,ax
    ;; si is the location relative to the data segment of the
    ;; string/char to display




    ;Moves 0 into the dx register to act as the counter for the outer loop
    mov dx, 0


outerLoop:
    mov cx, 6 ; Moves 6 into the cx register.
        loop: ;Loop label
    mov si, dotVariable ;Moves the dot variable into the si register.
    call writeString ; Calls the write string function which keeps executing by printing out a dot until the counter reaches 0.
    dec cx ;Decrements the cd regist
    cmp cx, 0 ;Compares the contents of the cx register and checks whether its contents are equal to 0.
    jge loop ;If the value in the cx register is greater than 0 jump to the loop label and execute the above procedure until cx is equal to 0 .
    mov si, spaceVariable ;Moves the spaceVariable into the si register which serves the purpose of adding a new line  since the dotVariable has 0,10,0 which indicates a new line.
    call writeString ; Calls the writeString function with the space variable effectively creating a new line.
    inc dx ; ;Increments the dx register by one.
    cmp dx, 6 ;Compares the contents of the dx register with 6 each time the loop runs.
    jle outerLoop ; If the value of dx is less than or equal to 6 it jumps to the outer looop;


    mov si, studentName ;Moves the studentName variable to si register
    call writeString ;Prints each character at a time until it encounters a null character at which point the process is repeated until no more strings remain in the buffer.
    mov si, studentCourse ;Repeats the same procedures mentioned above.
    call writeString
    mov si, favouriteMovie
    call writeString



    jmp $ ; Spin
writeString:
    mov ah,0x0E ; Display a chacter (as before)
    mov bh,0x00
    mov bl,0x07
nextchar:
    Lodsb ; Loads [SI] into AL and increases SI by one
    ;; Effectively "pumps" the string through AL
    cmp al,0 ; End of the string?
    jz done
    int 0x10 ; BIOS interrupt
    jmp nextchar
done:
    ret

    ;User defined variables.
    spaceVariable db  13,10,0 ;Null - terminated
    dotVariable db '.' ,0,10,0 ;Null - terminated
    studentName db 'Name: Martin Vasilev' ,13,10,0 ;Null -terminated
    studentCourse db 'Course: Computer Science' ,13,10,0 ;Null - terminated
    favouriteMovie db 'Favourite Movie: Ex Machina' ,13,10,0 ;Null -terminated


    times 510-($-$$) db 0
    dw 0xAA55