Repo: https://github.com/valdanylchuk/xcc700Hi Everyone! I just wrote my first compiler!
- single pass, recursive descent, direct emission
- generates REL ELF binaries, runnable using ESP-IDF elf_loader
- very basic features only, just enough for self-hosting
- treats the Xtensa CPU as a stack machine for simplicity, no register allocation / window usage
- compilable on Mac, probably also Linux, can cross-compile for esp32 there
- wrote for fun / cyberdeck project
Sample output from esp32:
xcc700.elf xcc700.c -o /d/cc.elf
[ xcc700 ] BUILD COMPLETED > OK
> IN : 700 Lines / 7977 Tokens
> SYM : 69 Funcs / 91 Globals
> REL : 152 Literals / 1027 Patches
> MEM : 1041 B .rodata / 17120 B .bss
> OUT : 27735 B .text / 33300 B ELF
[ 40 ms ] >> 17500 Lines/sec <<
My best hope is that some fork might grow into a unique nice language tailored to the esp32 platform. I think it is underrated in userland hobby projects.▲In case anyone interested, you can run (nommu) Linux on ESP32 Xtensa boards
https://github.com/jcmvbkbc/esp32-linux-build
ESP32-S3 N16R8 is <$5 on aliexpress:
- Dual-core Xtensa 240 MHz
- 16 MB NOR flash (eXecute-in-place supported)
- 8 MB (PS)RAM
- Wi-Fi 2.4 GHz 802.11n, Bluetooth
As well as Zephyr, NuttX RTOSes, MicroPython.
Cool! And I do think the world needs more C compilers. There is so much you could do with this language, but it needs to be disentangled from the C++ compiler behemoths. (yes, I now that there are other small C compilers)
reply▲isitcontent8 hours ago
[-] There is the TCC. Adapting that would probably be a faster path to a full featured C compiler on esp32 than building up my xcc700. This is more of an educational sandbox project.
reply▲I know, and there are chibicc, kefir, etc. .. and I have my own experimental C compiler.
reply▲I would love to see how you handle variably-modified types, the way I retrofitted them onto chibicc never felt quite right, and I've never seen another non-gcc/clang compiler fully support noplate's VM type patterns.
reply▲saidnooneever7 hours ago
[-] hats off. this is really easy to read and well written and easy to comprehend code imho because it only support basic features. its a really nice example to read through thanks. nice inspiration to see its possible to roll your own for this with a bit restricted featureset and goals :).
reply▲Cool, always refreshing to see different approaches to the same problem, and you learn so much by doing, this is more the kind of tinkering I will be doing in retirement.
reply▲ladyanita229 hours ago
[-] That's super cool! I have been wondering what could be done with ESP32 if it weren't for the lack of RAM.
As a fun of Rust, one thing that saddens me is knowing these things would be difficult to achieve with a Rust compiler, given the language seems to be vastly more complex.
Unless someone created a subset of Rust without (some?) safety checks, I guess.
isitcontent8 hours ago
[-] Right, Rust is more complex, and it is the complex bits that make it Rust. There are sure some shortcuts possible for starters, for example scope-based lifetimes like in early Rust versions, but still, to make it a worthwhile upgrade over C, it would take some intermediate representation, and definitely more than 700 lines.
There is a lively movement for coding in Rust for esp32, that works, just not on the device I think.
MobiusHorizons10 hours ago
[-] Very cool! What was the shell you are running in the demo video?
reply▲isitcontent10 hours ago
[-] Thanks! That is just my small custom experimental mini shell. This project started as a retro DOS-like cyberdeck, and first thing I tried to run there was DOS programs, which is why it looks like that. Only got to COM files, when I learned about elf_loader, so I now focus on that. I might extract and release whatever is valuable/reusable in that shell later on.
reply▲MobiusHorizons8 hours ago
[-] Yeah, very cool. I was thinking about possibly porting it to risc-v and using it on my fpga based core. I was trying to build a monitor style shell, but C like environment would be very cool.
reply▲isitcontent8 hours ago
[-] Porting to different CPU/bytecodes should be doable. Just keep in mind that in ESP-IDF we also get the dynamic linker and the libc for free (and any other C functions exposed in the firmware). On the other platforms, that may be some extra work for the compiler.
reply▲Yea I was understanding that hurdle, but thanks for the reminder.
reply▲Thanks for posting this here. I star’d the project. Getting a portable computer with a minimal flexible and previously well supported operating system was one of my goals for the esp32 as well. I’ll be watching for more.
reply▲Can this run ELF programs that are placed on the memory card?
reply▲isitcontent8 hours ago
[-] I only wrote the compiler. But ESP-IDF elf_loader component can do that, yes.
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