A program that does not need rentrancy because it doesnt use threads
should be most comfortable with a few bindings using a static array.
So dont worry.
Let people writing multithreaded applications find the solution
they need.
OTH, I like the idee of XaAES setting up a userdef stack per
application. Shouldnt be too difficult. The AES already needs
application specific data. I wrote AHCM for that purpose, when
XaAES itself was a usermode program.
Switching to user mode looks like a good idee for the KM.