[0] https://github.com/ioccc-src/winner/blob/master/2025/cable/p...
[1] https://github.com/ioccc-src/winner/blob/master/2025/cable/R...
>This VM implements an OISC - a One Instruction Set Computer. That instruction takes three signed 32-bit operands, a, b and c, and runs a program from memory m[] as follows:
1 PC (program counter) starts at 0
2 Fetch the next instruction (32-bit signed operands a, b and c)
3 If the low bit on any operand is set, remove it, and replace that operand with m[operand] i.e., a dereference of that address
4 Set m[b] = m[b] - m[a]
5 If m[b] is 0 or negative, set the PC to c, otherwise increment PC by 3 words
6 Go to step 2
https://github.com/ioccc-src/winner/blob/master/2025/ncw1/pr...
The author, Nick Craig-Wood, is the creator of rclone!
If you want to see how the sausage was made, here is the source:
https://github.com/ncw/ioccc-gameboy
You'll find an unobfuscated version (kind-of) there too. This the the one I actually worked on then I had a program squash all the variable names and squeeze it into the gameboy shape
The size limit for the entry was the killer. You are allowed 2503 non white space characters (a simplification - the rules are complicated) in IOCCC entries and 4K total code size. This isn't a lot to fit a Z80 processor and a GameBoy hardware emulator in!
I first wrote a full Gameboy emulator in C. It started out at about 6000 non white space characters. I then spent about about 100 hours work trying to get it to fit into the 2503 limit. For a long time I wasn't sure it was going to fit.
I decided making the emulator play Tetris (which is a fairly simple game) was the target so I stripped out features like the half carry flag in the Z80 emulator and the windowing system in the Gameboy emulation which Tetris didn't need. I also abused the C code terribly doing things with implicit int I can never un-see. I also got creative with the IOCCC rules which are implemented in a C program which checks your source and I spent some time reverse engineering that looking for loopholes! I discovered that the operators defined in <iso646.h> only count for one token which was very useful.
Once I had it small enough I had to supply some games to run with it. I created 4, a test program written in z80 assembler, a pi calculator (written in assembler), a 3d tic tac toe game (written in C with gbdk-2020) and a chess program also written in C. I discovered that quite a few open source games ran on the emulator too so I added a downloader for those where I could. Apparently not many games use BCD arithmetic - who would have thought!
It was a fun project.
GCC says there are a bunch of undefined symbols, first one being "R" right in the beginning:
typedef unsigned char u;
u w,X,T,D[1<<16],t[]=R,U=255;"The IOCCC has a rich history of remarkable winning entries created by authors who skillfully employed various techniques (often their own tools) to develop their code."
Also, the reverse is interesting: how well can they guess the function of the obfuscated code?
https://www.ioccc.org/2025/rules.html
It seems to refer to custom code generators. Why would they mean AI if they explicitly talk about a "rich history" (when AI wasn't available)?
Do I miss anything?
They also lack the creativity needed for those entries. Obfuscation is only one part of it. Coming up with the idea is another. Many entries also have special qualities that make them true works of art.
Have you tried it or are you guessing this?
For example:
if (x == 1 || x == 2) { ...
if (!(2+x*x-3*x)) { ...
[0] https://github.com/ioccc-src/winner/blob/master/2024/macke/p...
if (!(x/2-1)) { ...
this statement is equivalent to x==2 | x==3.
For example, x=3, 3/2 = 1 then 1-1 = 0 so that !(0) is 1 or true. Also for x=1, 1/2 = 0 then 0-1 = -1 and !(-1) = 0 or false.
I agree with your point in general though about size constraints.
if(x-1<2&&x)...
if((1<<x)&6)...
if(x<3&x)...
if(3%x&&x<3)...
if(!((x-1)*(x-2)))
if(!(x^1|x^2))...
if(!(x*x-3*x+2))Are you sure they still can't do it?
/curious though given the very nice conversation we're having here, why the parent topic gets down-voted. is neither off-topic, nor rude.../
Claude seems OK with it now, so I don't know whether that was a glitch but it was quite funny.
> You are free to use whatever tools you wish to write your code. This includes tools that are AI based, LLM (large language model), Virtual coding assistants, code generators, or similar tools, as well as your own tools. The IOCCC judges do not discriminate on the basis of the tools used to write obfuscated C code so long as you are the ultimate author of the code you submit.
- The number of winning entries and losing entries that get revealed later in public suggests that this number should be at least 50.
- The number of judging rounds, as the FAQ says, is at least 3 and possibly more. If each judging round eliminates about a half of entries, we should expect at least 10 submissions per each winning entries. I personally think the actual elimination rate can be as low as 1--20% at the end, but at least first few rounds should be easy so I think this is a good minimum guess: 1--200.
- The current number of individual judges is just enough for the three-digit number of submissions. It has a striking resemblance with typical academic conferences with typical acceptance rate, by the way! If there were thousands of submissions (like today's AI conferences...) there ought to be much more judges, and more importantly, more levels of judges so that each judge can do just enough work throughout the entire process. So this establishes the maximum guess: 1,000.
- My best guess is simply a geometric mean of two extrema.