[Simh] Fix for autoboot

[bsupnik at comcast.net]

The problem with Autoboot is that the simulator's initial state is not consistent.  The simulator is by default an extended memory KA655X, but the internal variable cpu_extmem is initialized to 0 rather than 1.  As a result, memory can be configured to large sizes, but the special CMCTL register needed by the firmware is not present.

To fix this problem, edit module VAX_CPU.C and change

int32 cpu_extmem = 0;					/* extended memory */

to

int32 cpu_extmem = 1;					/* extended memory */

Recompile and relink the system.

Thank you for bringing this issue to my attention.

/Bob Supnik