FPSIM fixed; 211bsd runs on systems without FPP

Some time ago I looked into running 2.11bsd on systems without a floating-point unit. The release notes state that this is untested and unsupported, and indeed it didn't work.

Robin Birch some time ago fixed part of the issues, see patch 434, but still the kernel paniced when the very first program was started. I managed to localize and fix the problem in sys/pdp/mch_fpsim.s. Steven Schultz right away issued a patch

All patches up to and including 445 are provided by Steven under

A patch level 445 system will now boot on simh for example on a
set cpu 11/70 nofpp 4m
configuration and work just fine, albeit a little slower.

It should thus also work on a real 11/70 without FPP. I heard of some 11/70 with non-working FPP's, so this may be good news for the owners.

2016-12-11: Update the URL of the patch archive.
For original note to 2.11BSD users see posting to cctech@classiccmp.org archived on