29 Oct
2010
29 Oct
'10
11:26 a.m.
On 2010 Oct 29, at 10:39 AM, Ethan Dicks wrote:
That all depends. Back in the day, what we did was not demand-paged
virtual memory (something supported natively on the VAX and the 68010
(but not effectively on the 68000) - some architectures have memory
management hardware that can "tell" if a reference is about to hit a
patch of virtual addresses that don't have physical memory mapped to
them and invoke some OS-specific routine to either allocate or pull
from storage what needs to be there and resume the instigating
instruction as if nothing happened (which is part of what
distinguishes the 68010 from the 68000 - instruction restart).
There have been a couple of indications it was the '10 that added the
instruction restart, but was the implementation in the '10 bug-free?
I didn't deal with the problem directly, heard about it from some
friends who were programming around it, and it would have been 1989, so
long after the 00->10 transition. My recollection about the issue was
there was a bug under certain conditions that was fixed in the next
version, as distinct from a 'new feature', but perhaps it was just the
way the problem was described to me or the way I understood what was
being said.