Simulators built with DONT_USE_INTERNAL_ROM defined will not have hte
binary of the needed ROM or boot components build into the simulator
binaries. However, they will automatically and transparently fetch the
neeeded ROM or boot code from the web when these binary files aren't
available locally.
These changes facilitate more robust parameter type checking and helps
to identify unexpected coding errors.
Most simulators can now also be compiled with a C++ compiler without
warnings.
Additionally, these changes have also been configured to facilitate easier
backporting of simulator and device simulation modules to run under the
simh v3.9+ SCP framework.
VAX 11/.750 Boot ROM code makes non-longword memory references to MassBus and Unibus register space. Minor changes were necessary to allow this behavior which was architecturally undefined behavior, but had real code which depended on it.
Added a BOOTDEV option to the CPU to reflect the 4 position boot device selection switch on real VAX 11/750 hardware.
The UBA750 initial state started with the UBA map registers validly mapping the first 256KB of RAM to Unibus space.
Added simulated PCS/WCS memory which boot code on some operating systems (Ultrix and other BSD derived systems) automatically loaded on the VAX 11/750. PCS/WCS was also automatically loaded by the newer versions of the BOOT ROMs.
