Stella Regia
Author: Rex / Camelot (aka Jesper Gravgaard)
Category: Christmas Challenge
System: C64
Language: Assembler (KickAssembler)
Len source code: 607 bytes
Len exe file: 66 bytes
Len code only: 52 bytes (valid for assembler only; length of executable without BASIC stub)
Instructions: Install vice, drag and drop the prg file into it.
Description:
- Draw 3 left diagonal lines and 3 right diagonal lines for 19 rows.
- The diagonal lines are wrapped at x=0 and x=18. The wrap-check uses an illegal 3-byte NOP to shave of a few bytes.
- Left & right diagonals are achieved by modifying code to alternate between INY & DEY.
- Always draws on the bottom line of the screen and use the BASIC SCROLL.
- When the loop is completed the first byte in the table incidentally has the value $02, which halts the CPU.
Comments: