Christmas Snowflake

Author: George Phillips
Category: Christmas Challenge
System:   TRS-80 Model 2
Language: Z-80 Assembler
Len source code: 540
Len exe file:    73
Len code only:   56
Instructions:
Can be imported into trs80gp in Model 2 mode.  But easiest just to run
from the command line:
trs80gp -m2 snow2.cmd
Description:
Uses a 1/4 bitmap of the snowflake and loops over X and Y looking up
each bit to display.  Needs a condition to get the outter pixels on
the long horizontal line.  Avoids printing a newline by looping over
80 columns rather than 19.
Comments:
Two cute things.  Orgs at the ASCII value of '*' * 256 so it can get
that constant for free.  And it so happens that value works well to
center the snowflake which is a lovely coincidence.