Re: Stacks, was Segments

On Sun, 19 Jan 2025 18:28:40 +0000
mitchalsup@aol.com (MitchAlsup1) wrote:

 
In My 66000 the code cannot read/write that other stack with LD and ST
instructions. It can only be accessed by ENTER (stores) and EXIT
(LDs). The mapping PTE is marked RWE = 000.
 
So, while you can still overrun buffers, you cannot damage the call/
return stack or the preserved registers !!

Not that I am a specialist in GC, but according to my understanding
the most common and the best performing variants of GC can not work
without read access to preserved registers. Compacting collector seems
to need write access as well.
As to return addresses, I would think that read access to stack of
return addresses is necessary for exception handling.