Vintage Computing Christmas Challenge 2025

Author: baz4096
Category: Christmas Challenge
System:   Acorn BBC Micro
Language: BBC BASIC 2
Len source code: 118
Len exe file:    118
Len code only:   118
Instructions:
Using a BBC Micro emulator, insert the DFS ssd disk image and perform a Shift Break, or click the following link and type MODE1:RUN

Description:
The asterisk X/Y positions are encoded as 4 bits high/low in chars, except for the non-printable ones that are poked into memory manually. Program then loops through these values several times, flipping +/- signs and swapping x/y to perform horizontal/vertical and diagonal reflection maths. Subsequent X/Y are then printed to screen.
Commments: