[cctalk] Re: Classic computers with more than one stack pointer, but not FORTH machines.

An interesting variation of that is the Philips PR8000, which has 8 general registers (well, one of the 8 is the PC, like on the PDP11) though no stack. But actually it has 8 sets of 8 registers, one for each processor priority level. So an interrupt automatically preserves the previous registers, and the interrupt handler address is simply the value found in R0 (the PC) for that level.