[Microbit-Python] Heap size

[Mark Shannon]

Hi,

I guess this is a question for Damien.
How is the size of the GC heap determined?

The code is here
https://github.com/bbcmicrobit/micropython/blob/master/source/microbit/mprun.c#L78
but where does the magic constant 9820 come from?

I'm planning on doing some experiments with a cut-down version of the 
DAL, and I would like to see how much more heap we can get.

Cheers,
Mark.