[Info-vax] Kittson question

[JF Mezei]

On 14-12-31 20:57, Simon Clubley wrote:

> An emulator for these very early ARM MCUs would have to take this into
> account and if the VAX architecture allowed similar use on some models,
> then I can see why a commercial emulator, which wants to mimic the
> original hardware as closely as possible, would consider that overhead
> to be acceptable.


Say i am on a real Microvax II, and I have a pointer variable that
contains a valid 24 bit address as well as my age in the high order 8 bits.

Wouldn't that simply generate an invalid access error and kill my
application ?


Would it be fair to state that the emulator would only need to trim high
order bits off addresses when kernel mode code tries to access physical
memory ?

Wouldn't virtual memory access always get translated to physical memory
adfdress that is pre-validated and not contain redundant bits in the
virtual address page table ?