Snowflake Bitmap Carry
Author: Andre Miller
Category: Christmas Challenge
System: C64
Language: Assembler (ACME)
Len source code: 2173
Len exe file: 73
Len code only: 69
Instructions:
Use Vice (x64 program.prg). Program uses an autostart vector, after loading with LOAD"*",8,1 it will start automatically
Description:
Uses a bitmap to represent left half the columns of the snowflake, which is then mirrored left to right.
One byte is used for each half (8 bits), which excludes the edge and center to save space.
Checks are done to print the edge and center, using stack to store carry flag values, used later in loop.
Carry flag used to determine if "*" or " " should be printed, looping through bits use shift, which sets carry flag.
Left and right printed simultanously, using kernal pointer to current line and a left and right offset, pointer updates
when kernal routine is called for CRLF.
Comments:
Finally managed to do a submission in time! Attempts to also mirror top and bottom resulted in a larger program.