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

[Paul Koning via cctalk]

> On Feb 20, 2025, at 1:52 PM, paul.kimpel--- via cctalk 
> <cctalk@classiccmp.org> wrote:
> 
> What is the problem with ISRs running in a user stack? The ISR runs, exits, 
> the stack is cut back, and net effect on the user's stack is zero.

A stack access fault in user mode kills the process, in kernel mode (certainly 
in an ISR) it kills the whole system.  You can't leave the integrity of the OS 
at the mercy of the application having a valid stack.

        paul