Love it, very Zachtronicesque. If the author is reading, here are couple of improvement ideas:
* Show the level number somewhere so its easier to discuss with others
* Add some way to know how well I did on the level, either by having some leaderboards or rating system/target cycle count
* Allow pausing the execution when running
* Not sure if it would make sense to have full 8-bit color palette instead of 4 bits. Probably does not matter to game design too much
I think it might be neat idea to implement this on real hardware with these sort of rgb led modules http://i.imgur.com/4YnDwWu.jpg and some way to input code, maybe row of toggle switches Altair/PDP style or small keypad like in KIM-1
Visiting that webpage causes my SUSE Firefox 45.0 browser to say
"You need a browser which supports WebGL to run this content. Try installing Firefox."
Probably a driver issue. Firefox 45.0 supports WebGL, but it may be disabled on your machine if it can't find a suitable OpenGL driver. For reference, the site worked fine on my Ubuntu 15.10 machine, Firefox 45.0, Intel GPU.
I looked at this a couple of times today before finally digging in and as I completed each level I looked forward more and more to the next level. And then there were no more levels, far sooner than I expected. I hope the author adds more in time.
Edit: Oh and earlier today after having looked at it many times I bought http://www.lexaloffle.com 's combination of Voxatron and Pico-8. I've spent sometime today learning about Pico-8 (to which I'm going to limit my attention for now) and I think anyone interested in the linked game might be interested in these as well.
Real x86 is very different; you have limited registers (especially 32bit x86), very weird variable length instruction encoding, gazillion different instructions, memory access takes significant amount of time. Of course having near infinite amount of memory compared to the 256 bytes of BOX256 changes the way you program your code too.
1. If you start every thread at 0x00 and make the first N commands "THR @00", you get 2^(n+1)-1 threads running by the time your first thread exits the chain of THR commands.
2. You can use a single array MOV instruction to set a range of program counters, effectively causing every thread to jump to a set position.
So in the first 5 cycles I start 31 threads, then my main thread drops into a loop where all it does is set every thread's position (including its own) to a start point every 2 cycles. Every single thread is now a 2-cycle loop with no JMP cycle spent to return to the start each time.
Then I simply make 16 loops of:
PIX counter color
ADD counter 1 counter
with color being one of two memory positions, which the main thread swaps out each loop. I initialize counter such that each thread is doing its own row of the output (0, 10, 20, etc). The leftover threads I don't actually want (but it's hard to fine tune the thread count, so I left them in), so they share the first thread's loop. The repeated actions are effectively a noop.
Note that, due to space constraints, I use the unused 4th byte of each PIX instruction as the counter for that loop.
Doing this got me to 0x24 cycles. I shaved a further 4 cycles by using the leftover space to add 4 more loops. These ones run vertically and operate on the last two columns (two threads doing one column together). By the time the row-moving threads have reached the 2nd last column, the column-moving threads have finished the last two columns, and so the program is finished 4 cycles earlier.
I think I could get another 2-cycle saving if I fine-tuned the number of threads started, compressed everything down again and got another two column-moving threads.
The bigger improvement is converting the whole thing to 1-cycle loops instead of 2-cycle, and having half the loops incrementing the counters and the other half doing PIX instructions. This might just be possible in the available space if I've run the numbers correctly, and would result in a total time of 0x14.
I started optimizing by making separate increment/render threads with a buffer and copy, and then doubled it to 4 threads. It's currently at 0xDD cycles but I don't think I'm going to take it farther:
Awwww this is great stuff. I would love to hear your thoughts on how the language could be changed/improved to make puzzles and optimizing even more fun.
The biggest thing for me is being able to save/load solutions. I ended up keeping multiple browser tabs open as I tried to tweak solutions / attempt different puzzles.
As for the language itself, a MOD operation to go with the DIV operation is useful. bitwise AND / OR / NOT / XOR could be interesting.
Something that would make threads a lot more versatile would be some way to have them behave differently from one another even when executing the same code.
Perhaps a new instruction like JTI X Y: Jump if Thread Id (defined as 0xFF - location of program counter) is equal to Y
Or much more versatile but harder to account for in opcodes: a new prefix #XX which behaves like @(XX + thread id). So you could, for example, write 0x42 to a per-thread slot in an array starting at 0xA0 by doing "MOV 042 #A0"
For making the puzzles interesting: The problem is most shapes and images can simply be described in memory and subsequently brute-force PIXed in sequence. After the simplest puzzles, the trick is having images that do not fit easily in memory and require procedural description. Checkerboard is a good example here. What about something like fizzbuzz but described in colors (like this: http://imgur.com/RMEaKAg)? Or tricky questions where a seemingly random image actually has a simple pattern (like this: http://imgur.com/TbTPZnh (spoilers here: http://imgur.com/73De5QF ))? Unfortunately you're very limited as there's no actual input; the program's exact output is always entirely known.
Several people here have mentioned TIS-100: It's not the exact same thing as what you're doing, but it could be an interesting thing to compare with if you haven't played it yet.
EDIT: Just for fun, my best time for that second puzzle I posted is 0x103.
The copy-pasting to clipboard doesn't work in the webgl for browser security reasons, but you can download a Windows build that has working copy to clipboard. I'll make an OSX build later also. See the link here: http://bit.ly/1V1PiHt
How to make threads operate differently on same code is interesting. I don't really want to do another prefix, because I want to keep the realism of 255 opcodes and I've already used 128. The permutations of new prefix would not fit anymore. I also like the JTI suggestion, but perhaps it doesn't go as far as I would like.
Currently I'm thinking that maybe in addition to program counter, the thread would have another slot where it can define "memory offset". You could state the offset when you start the thread, but it is also modifiable later on, as its in memory. You would call for example "THR @023 010 000", which would essentially mean that for ALL operations for that thread, ALL memory addresses get a offset of +010. I think this is very close to what you suggested with threadID. I think the offset would live next to program counter (FE & FF). Do you think that would work?
I've played TIS-100 and named this game similarly BOX-256 as a homage, since TIS-100 pretty much inspired the whole thing. It's a wonderful game.
Great ideas on the new levels. I will shortly update with more levels and I'll be sure to add your suggestions in to the mix :)
You can't access localstorage or anything for persistence? Can't create a popup with copy-pastable text? Any means of input or output from the game short of screenshots and manual typing at all?
The "all operations offset" sounds tricky but interesting. It'd be problematic in a typical usage scenario, but probably work well with my horrible "every line of code runs in a 1-cycle loop on its own thread" style :P
where THR instruction would store a value that is visible only to child in some memory location, in this example value 001 would be stored at @A0, which is then used to distinguish the threads in a conditional jump.
What's really funny is when the program's trivially paralellizable (any of them where the entire thing to draw fits in memory) and the main thing your threads are doing is to start more threads, then finally all the threads do 2 draw instructions each.
* Show the level number somewhere so its easier to discuss with others
* Add some way to know how well I did on the level, either by having some leaderboards or rating system/target cycle count
* Allow pausing the execution when running
* Not sure if it would make sense to have full 8-bit color palette instead of 4 bits. Probably does not matter to game design too much
I think it might be neat idea to implement this on real hardware with these sort of rgb led modules http://i.imgur.com/4YnDwWu.jpg and some way to input code, maybe row of toggle switches Altair/PDP style or small keypad like in KIM-1