@typeswitch it used to be pretty much normal to have 2 or 3 dedicated stacks for different purposes (see e.g. prolog machines). Kinda killed by (among other factors) x86's single SP reg. C and now LLVM&rusts don't help much either.
I hope we could see some cool new multistack code on risc-v (no big network effects yet, and there is no dedicated stack support needed in the cpu)