// lib:
// print.dsa

// usage:
//
// include print "<relative path>""
//      
// usage for print:
//      push (register containing address of string)
//      push pcx
//      jmp print::print
//
// usage for reset:
//      push pcx
//      jmp print::reset

dw display: 0x20000
dw current: 0x20000

// prints the given text to the screen.
print:
    push bpr
    mov spr, bpr

    ldw bpr, rg0, 8
    ldw current, rg1

print_loop:
	ldb rg0, acc
	stb acc, rg1

	addi rg0, 1
	addi rg1, 1

    cmp acc, zero
	jne print_loop
    jmp end

// return
end:
    stw rg1, current
	
    mov bpr, spr
    pop bpr
    return

// resets the cursor position on the screen
reset:
    push bpr
    mov spr, bpr
    ldw display, rg1
    jmp end

clear:
    push bpr
    mov spr, bpr
    // display size = 2000 bytes / 500 words
    lli 500 rg0
    ldw display, rg1

clear_loop:
    dec rg0
    stw zero, rg1
    addi rg1, 4
    cmp rg0, zero
    jgt clear_loop
    jmp end