This routine draws a series of dots, using the intensity already set up in $C828. The format for the dot list, which is pointed to by the X register, is:
( rel y, rel x), (rel y, rel x), .....
The number of dots-1 to draw is specified in $C823.
DP = $D0
X-reg points to the list of dot coordinates
$C823 specifies the number of dots to draw
X-reg points to next byte after list