On 20/3/23 14:57, Kalvis Duckmanton wrote:
On 18/3/23 06:26, Rhialto wrote:4. Perhaps this is the reason why the whole thing doesn't work if you have a lot of RAM: if we take the comment "beyond the end of the system page table" at face value, then maybe such a large memory configuration causes the page tables to grow enough that the T_PTELEN trap does not occur. Instead there would be some other trap type.
So just further to this - I noticed that when SIMH is configured with 512MB of memory, the calculated size of the system page table ends up being a bit larger than the 2^21 entries needed to map all of system space. (The value I saw in the system length register was 0x23eef0 (2^21 is 0x200000) - I think in such a case a length violation fault will never be generated.)