Dot_List ($F2D5)

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.

ENTRY:

DP = $D0

X-reg points to the list of dot coordinates

$C823 specifies the number of dots to draw

EXIT:

X-reg points to next byte after list

$C823 cleared

D-reg trashed

Source