7
Meeting Seed7
(genodians.org)
DOS + BIOS boot (hybrid binary)
Repo | day01.asm | day01.c (prototype) | .COM download
Written in x86-16 assembly. Works as a DOS program but also as disk image for older PCs with BIOS support (or older VMs). Getting this setup to work was tricky, especially since when I started this, I had only basic x86-16 experience! Needless to say I've spent much time staring at hex numbers.
The very start of the file determines if it's running in DOS or as a bootloader, in which case it'll have to load the remainder of the file from disk and rearrange the memory layout to emulate the DOS situation.
Right now this is using just one segment of memory (64K). Input data is compressed using a custom run-length encoding scheme. The compressed background image is directly decoded into the VGA framebuffer, after which it is overwritten with the decompressed input file. Space is tight!
My main goal is to finish a few days at least with one or more game consoles supported (GameBoy Advance would be cool) and to do some cool palette tricks, like a day/night transition or animated water and stars.
What bothers me about this specific question, apart from it being dated, is that it breaks the rules of these kind of riddles. They're implied to be in a sort of frictionless sphere universe, the whole preposition is silly except as an abstract puzzle. To then rely on the physical properties of real lamps is cheating. You're supposed to ignore all the real-world aspects of the setting except that one.