| process | description |
|---|---|
| extend_snake | extend the head of snake |
| move_snake | extend the head of snake and reduce the tail |
| generate_food | putting a new food on the map |
| coordinate_plus_direction | calculating the new coordinate according to olds in ax and direction in bl |
| check_coordinate | checking whether the coordinate is still in map, affect cf |
| draw_block | drawing value in dx to the block of row bh column bl |
| draw_string | drawing the string which pointed by the effective address in di, to row bh, column bl, with color dh |
| draw_GUI | drawing the outer GUI of the game |
| draw_content | drawing the whole map, including the snake head, body, and food, wall |
| draw_score | drawing the numeric score at row bh, column bl |
| get_input | getting the user input from keyboard buffer and modifying direction |
| get_map | getting the map value of position ax, saving it to bl |
| set_map | setting the map value of position ax to bl |
| reset_screen | setting the display method to "80*25, 16 color" to reset the screen, and hiding the cursor |
| get_rand | getting random number not bigger than al, and saving it to ah |