These routine draws a series of patterned vectors. The pattern to use must already be specified in $C829. The number of vectors to draw minus 1 must be specified in $C823. The vector list, pointed to by the X register, has the following format:
rel y, rel x, rel y, rel x, ...
Draw_Pat_VL_d starts at the (y,x) coordinates specified in the D register and ignores the first pair of coordinates in the vector list.
DP = $D0
X-reg points to the vector list
$C829 contains the line pattern.
X-reg points to next byte after list