4 Aug
2008
4 Aug
'08
2:27 p.m.
On Monday 04 August 2008, Sean Conner wrote:
It was thus said that the Great Jim Brain once
stated:
The PDP-11 doesn't support restartable instructions either. You don't
need restartable instructions to support an MMU, only to support
virtual memory type operations. For example, my Z80-based Altos 8000
has a bank-switching MMU that could operate the same way as an MMU on a
808[68] would.
Pat
--
Purdue University Research Computing --- http://www.rcac.purdue.edu/
The Computer Refuge --- http://computer-refuge.org
Tony Duell wrote:
If such a think existed, it would have been an external circuit,
and would have been very hard to support since the 8086 did not
include support for restartable instructions (same situation on the
68000). No it doesn't, given that a PDP11 address to a
program is always
16 bits. The 18 or 22 bit phuysicall addresses were created by
the MMU.
Did an MMU exist for the 8086?