Debug Console Extension support

[x64k]

Hey,

So I'm using sbi in a toy project of mine and I found myself in need of a debug console. SBI legacy extensions expose getchar and putchar but since they're technically optional now and I don't want to find them deprecated from under my feet months/years from now, I figured I'd take a look at the Debug Console Extension (DBCN).

Long story short I have a basic implementation working, and I'm wondering if there would be any interest in merging support for this feature upstream..

I've tested it for all of five minutes and it seems good enough for what I need. It's not ready for a pull request yet, I'd need to come up with a better buffer address passing mechanism (DBCN uses a weird, split base-offset convention and I'm not entirely sure how to go about translating between references and that at the moment), and write tests.

I'd be happy to do both if you think this feature would be useful to others. I just figured I'd ask before opening a pull request.

Thanks!

[repnop]

I actually have a work-in-progress branch for version v2.0 of the SBI spec that I've been working on over the past little while and already have the debug console implemented, but there's some unpushed work and I still need to finish the rest of the added extensions to the new version of the spec, but I'm hoping to have that done relatively soon. I'll then have some people review it and then publish a new version of the crate (there's some additional breaking changes as well), so keep an eye out!

[x64k]

Oh, that's great to hear! I'm looking forward to it. If I can lend a hand with anything, poke me. Cheers!

[repnop]

@x64k sorry to get around to this so late, but I finally published a release candidate version of the crate if you'd like to try it out and give any feedback! https://crates.io/crates/sbi/0.3.0-rc1

[x64k]

Hey, nothing to be sorry about, this isn't some megacorp project :-). I'm traveling this week, but I'll be back home in a few days, and I should at least be able to look over the diff next week if it helps in any way.