search

tinygo-org / tinygo

Go compiler for small places. Microcontrollers, WebAssembly (WASM/WASI), and command-line tools. Based on LLVM.
https://tinygo.org
Other
15.48k stars 913 forks source link

Switch to CMSIS 5? #397

Open QuLogic opened 5 years ago

QuLogic commented 5 years ago

The license for CMSIS 4 is rather complicated, mostly due to being a custom license, with separate terms for different parts of the repo. CMSIS 5 is much simpler though, because it's just one license, Apache 2.0.

CMSIS 4 also hasn't been touched in 3.5 years, though I'm unsure if the headers used require all that much care.

It would be nice if tinygo could switch to using CMSIS 5 instead. Unfortunately, I don't have any nrf hardware to test, or I might attempt this myself.

deadprogram commented 5 years ago

In theory, that sounds nice. But we need to work with vendor provided SVD files for each for the platforms we support, and there are not CMSIS 5 versions of all these files. At least I could not find them anywhere.

aykevl commented 5 years ago

I don't think the CMSIS version here is related to these SVD files. The main reason why we need CMSIS is for a few header files for the nrf, but not much else (example: we don't use the CMSIS interrupt macros but instead use ones written in Go). That will likely change with improved CGo support, though: existing libraries will likely use CMSIS.

For me, the main reason why I haven't switched the repo over was that CMSIS 5 is much bigger. That's less of a problem now because (I think) more people use the release builds and we probably only need to include a small part of the whole CMSIS system.

QuLogic commented 5 years ago

You're right, the new one is pretty big to clone. The checkout itself is not too much different:

$ du -hsc lib/CMSIS* --exclude=.git
294M    lib/CMSIS
326M    lib/CMSIS_5

whereas the repo itself is triple:

$ du -hsc .git/modules/lib/CMSIS/ lib/CMSIS_5/.git/ --exclude=lfs
63M .git/modules/lib/CMSIS/
203M    lib/CMSIS_5/.git/

However, they did move a lot of stuff to git-lfs:

$ du -hsc lib/CMSIS_5/.git/lfs/
192M    lib/CMSIS_5/.git/lfs/

so you can disable it to get a smaller repo:

$ du -hsc --exclude=.git CMSIS_5_no_lfs/
94M CMSIS_5_no_lfs/
$ du -hsc CMSIS_5_no_lfs/.git
204M    CMSIS_5_no_lfs/.git

Unfortunately, I don't know if you can set that for a submodule.

QuLogic commented 5 years ago

Alas, I've still not figured out a way to disable lfs (other than not having it installed or explicitly skipping it during a clone), but if you want to test the clone size, you can try with https://github.com/QuLogic/tinygo by cloning the cmsis5 branch.

aykevl commented 5 years ago

@QuLogic slightly unrelated but what are your thoughts on newlib? The license story of that library is really messy but it is used everywhere and I intend to include it in TinyGo at some point as a libc on embedded devices (so you can do printf in a C file added with CGo).

QuLogic commented 5 years ago

It is rather messy, but fortunately, they're all free licenses and this has already been verified as there are packages of it already.

Would this be added on microcontrollers or arm, or both?

aykevl commented 5 years ago

Whoops forgot to reply here.

It is rather messy, but fortunately, they're all free licenses and this has already been verified as there are packages of it already.

Glad that this is sorted.

Would this be added on microcontrollers or arm, or both?

Cortex-M microcontrollers and possibly other microcontrollers: Linux/ARM already has a libc. At the moment, the support for CGo is very weak but if we want to make it usable, there has to be some sort of libc.

QuLogic commented 5 years ago

I recently came across picolibc, which you might be interested in.