Snowflake in the Night

This is my entry for the Logiker's Vintage Computing Christmas Challenge 2025 (VC³ 2025). It placed 20th overall and 3rd on the PC platform.

System: PC, MS-DOS. Language: Assembler (fasm). Code size: 59 bytes.

The coord_generate branch was an alternative approach I considered, but the version from the coord_enum branch made it into the final release.

         *
       * * *
  * *   ***   * *
   **    *    **
  ***  * * *  ***
     *  ***  *
      *  *  *
 *     * * *     *
  *     ***     *
*******************
  *     ***     *
 *     * * *     *
      *  *  *
     *  ***  *
  ***  * * *  ***
   **    *    **
  * *   ***   * *
       * * *
         *

How to compile

Just use FASM:

fasm.exe snowflk.asm snowflk.com

How does it work

The code iterates over a near-full-screen area (80x19 - 1). For each point, it calculates coordinates relative to the snowflake's center and tests conditions on their squares (X^2, Y^2) and sum (X^2+Y^2). Side branches are stored in a 6-byte table that also serves as executable code (initializes counter). Output via int 29h.