Draw_VLp_scale ($F40C)

This routine processes the vector list pointed to by the X register. The first byte in the vector list is the scale factor. The vector list has the following format:

scale
pattern, rel y, rel x
pattern, rel y, rel x
. . .
. . .
pattern, rel y, rel x
0x01

The list is terminated by a pattern byte with the high bit cleared.

ENTRY:

DP = $D0

X-reg points to the vector list

EXIT:

X-reg points to the terminator byte

D-reg trashed

Source