Anyone here ever written a C compiler? Assembler? Want a challenge? #whistlesInnocently - ThreadSky

lockfarm.bsky.social • 14 days ago

Anyone here ever written a C compiler? Assembler?

Want a challenge?

#whistlesInnocently

Comments

retr0.id•14 days ago

Tell me more...

lockfarm.bsky.social•14 days ago

I'm looking at a new ISA (generally ARM-1-ish) to sit somewhere between accessible 'retro' 8-bit systems and modern "might-as-well-run-Linux-on-it" devices.

It's for a specific need and I can write an assembler (another side project!) but wondered about what else might be done in the way of tooling

evogd.bsky.social•14 days ago

I've written a z80 assembler and disassembler, started on a basic c computer targeting the z80, but then put more energy into a "usable" two operator type intermediate language for fun. I got part way through before backburning it for a bit

bugbear6502.bsky.social•14 days ago

Bonus points - write a C compiler targeting the 6502

lockfarm.bsky.social•14 days ago

I've seen a few 8-bit C compilers, but they're either very slow, or not remotely compatible with modern C so you might as well develop your own more suitable language and not bother with jumping through hoops to be 'C-ish'..

retr0.id•14 days ago

I think llvm-mos is actually decent: https://github.com/llvm-mos/llvm-mos

Unlikely to beat hand-written assembly but not slow either

bugbear6502.bsky.social•14 days ago

"8 bit" is fine, as long as you've got address register(s) that can access the whole memory range.

There are "OK" C compilers for z80 and 6809.

rexcm.bsky.social•14 days ago

I attempted to write a C compiler for my PDP-8. Well technically it’s a C -> PAL transpiler. Furthest I got was unary, binary, and trinary operators. It supports 12-bit “integer” variables and a single main function that takes no arguments and returns an int. Code generation was probably the hardest

rexcm.bsky.social•14 days ago

It compiles to an assembly language (PAL III) which I’ve also written an assembler for. It was much simpler and also very fun to write. It generates instructions for a custom PDP-8 that I built with discreet logic chips. Also a lot of fun!

breakintoprogram.co.uk•14 days ago

I’ve written a couple of assemblers and disassemblers in my time. Never attempted a C compiler.

lockfarm.bsky.social•14 days ago

Yeah, I've got a fairly standard "emulate, disassemble, assemble" project pipeline that I've repeated a few times, in a few different languages...

thelastpsion.com•14 days ago

It's on my To Do list, but I'm quite far away from actually starting.

Having said that, I am intrigued...

gordon.plus•14 days ago

Both. But I don't want to do it again right now...

antronicsltd.bsky.social•14 days ago

SDCC?

https://sdcc.sourceforge.net/

lockfarm.bsky.social•14 days ago

Hmmm... I'd forgotten that one... 🤔

antronicsltd.bsky.social•14 days ago

No

And No.

😜

viciousnarwhal.com•13 days ago

I'd really have to dig up those yacc skills I haven't used in years.

rhydermike.bsky.social•13 days ago

You've just made me pull this of the shelf for a few minutes. It's been there for about 35 years to be honest. https://openlibrary.org/works/OL15165587W/Mastering_Interpreters_and_Compilers

rhydermike.bsky.social•13 days ago

I don't have much expertise in this area, but I presume that you'd be best compiling to an intermediate language so that you can take full advantage of the existing toolchains? But if you want to use a unique ISA as well, perhaps you'd be better off doing everything from scratch.

lockfarm.bsky.social•13 days ago

I was part of a team that wrote a (high level language) compiler to Java byte-code, but that's a whole different ball-game.

I seem to be doing everything from scratch with this project :)

jon-jones.bsky.social•14 days ago

A very basic compiler isn't too hard. (I'm old skool Lex & Yacc) as it's close to a translator. It's when you want to start adding even the simplest of optimisations that you start sliding down a very deep rabbit hole.

anderszapac.bsky.social•13 days ago

Yeah, compiler theory was one of the courses in Uni. I think we used Flex and Bison but it pretty much is the same. No optimization and I don't remember which processor was used, possibly 68K as we already had other courses in assembly language etc using 68K.

jon-jones.bsky.social•13 days ago

The other challenge is how far into C's dark corners do you want to venture? If you can restrict yourself to a slightly simplified/common core of C you'll be fine. If you want to compile every pathological dark corner abused by software you might want to just write a new backend for gcc or LLVM.

lockfarm.bsky.social•13 days ago

TBH it wouldn't necessarily have to be C, so much as a high-ish level language that wouldn't scare people trying to write games. But since most people in that bracket will want to grab code snippets from elsewhere, it makes sense to pick something pretty mainstream and compatible.

lockfarm.bsky.social•13 days ago

A while back I wanted to get Lua running on the eZ80 - that turned out to be a nightmare since Zilog's "Standard C compiler" for the chip was anything but standard. It was a huge ask, but if you're offering a high level language, the whole point is to make things simpler for devs..

dacut.bsky.social•14 days ago

In the late 90s/early 00s, I was keeping an eye on C--, a dialect of C for making compilers. Sounds like it’s mostly abandoned, though. https://en.wikipedia.org/wiki/C--

I’ve tried to wrap my head around LLVM IR, but work and life keep getting in my way.

rascalfoxfire.bsky.social•14 days ago

Currently in the middle of doing that since i am just tired of porting all software between my different ISAs by hand in hexadecimal

philpem.bsky.social•14 days ago

Done an assembler, and a C-like-language-to-bytecode translator... I'm curious what you're up to.

lockfarm.bsky.social•14 days ago

My long term goal is a system that is completely self-hosting for writing games and apps, that's powerful enough to get some nice results, but not so complicated that you can't understand it.

Inspired by the retro scene, but also modern ideas like the PlayDate.

jamesots.com•14 days ago

I've written an assembler, and I reckon a non-optimising C compiler would be fairly straightforward. I'm not after a challenge involving either of those, though!

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