Of course the routine could be written to be quicker (copy blocks opcodes or zero page ...)
The picture is displayed with a 65C816 cpu and a 65C816 routine, it loads from sdcard or from usb (from PC) if we want (it solves emulators issues, because program can be executed on the real hardware directly).
I'm getting quite far ahead of myself here, but I'm currently working on the 65816 in Clock Signal, which means it'd be essentially trivial to add support for at least an 65802 to the Oric.
So if there is any extant code, it'd be great to know more about it. Though a full-on Twilighte board might be a bit beyond me.
EDIT: that's all done now. It'd be trivial to add 65802 (i.e. 65816 with a 16-bit address bus) support to my emulated Oric; I can do it for a one-off build by changing two lines. But mine isn't an emulator that offers a trillion settings just because it can — that means I can offer a 65802 Oric if ever there is software to use it with.
EDIT2: oh, go on then, secret feature. If you pull master now and build the SDL version, you'll notice that you can now create a new Oric from the command line with a 65816. It's just useful for me to have one machine that actually tests that segment of code before I get started on a genuine 65816 machine. No current guarantees as to correctness, but test suite results are generally good.
EDIT3: though I should probably add that I found limited 65816 tests and am only now working on my first 65816-based machine. So possibly wait until the next release if you want a 65802 that most likely works correctly.