Print function will print to random locations

[firestar4204]

My print function will work well for the first few calls, but it will start printing to random locations on the screen. I'm not sure what's going wrong as my code is nearly identical to the code here (or maybe not, I can't really tell). Anyways, the code is here: https://github.com/firestar4204/houndos/blob/master/drivers/screen.c

Thanks!