[Oberon] Project Oberon 2013 on RISC-V

[Rikke Solbjørg]

Hi,

> Thanks. The “Alt" functionality is now back! It would be good if this change were
> also back-ported to the emulator - for the Mac users out there..

Added it back in now, thanks for the diff Michael :) There was a version 
of this in there, where if you held alt and left-clicked it would 
simulate clicking the middle mouse button. But I think that didn't quite 
match the behaviour expected from the emulator it's based on, so this 
solution is better - I'd never actually used the feature myself, as I 
always had a middle mouse button at hand...

> No, that’s not it. It’s also slower on older versions of macOS. Also, on the same
> machine oberon-risc-emu (RISC5) version is much faster.

Thanks for bringing this to my attention! It didn't run this poorly on 
my machine, so it never registered as an issue to me, and emulator speed 
was never a focus anyway. However, if it is this bad then a fix is 
definitely warranted.

I looked into it, and from what I can tell it is entirely because of how 
I implemented logging. Basically, it would always call a logging 
function, and only the actual I/O part was skipped if logging was turned 
off. After removing logging altogether, the difference in speed and 
responsiveness between the RISC-V and RISC5 emulator became 
imperceptible to me. I've pushed a fix that remedies this issue now by 
making logging more efficient - it works well on my machine, and 
hopefully it solves the sluggishness on your machine too.

Rikke