Defines a sprite:
n = Sprite number (1 - 32).
p = Pattern number (0 - 127 for 8x8 sprites, 0 - 31 for 16x16 sprites).
xp = Horizontal position of sprite centre (0 - 4059).
yp = Vertical position of sprite centre (0 - 4059).
xs = Horizontal speed (-128 - 127).
ys = Vertical speed (-128 - 127).
c = Colour (0 - 15).
Include file: mtxscrn.h