It also modifies the HP 2100 and PDP11 multiplexers to add serial support as demonstrations of the capability that, one day, might be extended to all simulators. I have tested the HP support, but I relied on Holger Veit to test the DEC stuff, so I can't guarantee that it works. I also relied on Holger to test under Linux, so the same caveat applies.
The changes needed in the device simulators are relatively small. For example, if you look at the patches for "hp2100_baci.c", you'll note that most of them are documentation changes. The only things of note are:
- an expansion of the TMXR initializer
- additional code in the "attach" routine to try attaching a serial port
if attaching a socket fails
- additional code in the "detach" routine for the same reasons
The HP MPX device (hp2100_mpx.c) needs a tiny bit of additional support from the ATTACH and DETACH commands. Specifically, SCP was modified to set a flag ("sim_unit_ref") to indicate whether ATTACH MPX or ATTACH MPX0 was done, i.e., to differentiate between a device and a unit attach (recall that SCP treats these as both referring to unit 0). This is needed because the socket attaches (logically) to the device, whereas a serial port attaches to a line. Without this flag, the attach routine cannot differentiate between ATTACH MPX and ATTACH MPX0, as the distinction is lost by the time the VM's attach routine is called. This support isn't needed for the HP MUX device because the socket attaches to a different device than the lines do.
MPX also requires a bit more work due to the capability to mix serial and Telnet lines on the same multiplexer (BACI is a single-line terminal device).
The attached PDF contains revisions to the "Writing a Simulator for the SIMH System" publication that documents the additions and changes to the multiplexer library for serial port support. User documentation for serial port support currently exists only in the initial comments in "sim_tmxr.c"; I will add the appropriate text to the "SIMH User's Guide" if we decide to add this to the release version.
Added Message Suppression flag for status values, including providing a -Q option to the RETURN command to return with a message suppressed status
Added Do command file default extension of .sim (from Dave Bryan)
Added -O option to DO command file invocation which causes the caller's ON state and actions to be inherited in the newly called DO command file
Added Command Line expansion to include a %* which expands to the whole set of arguments (%1 ... %9)
Relaxed Command Line argument substitution (delimited by %'s) which cause environment variable lookups to first lookup the literal name provided and if that fails, lookup the name upcased.
Added a SIM_VERIFY special Command Line expansion variable which expands to "-V" when command echoing is active
Added a SIM_MESSAGE special Command Line expansion variable which expands to "-Q" when error message display is suppressed
Added Command Aliasing, which causes the initial token on a command line to be looked up in the environment variable table, and if it exists to substitute the expansion for the initial token.
Changed environment variable defining (with SET ENV variable=value) to always upcase the variable name.
Added SHIFT command which shifts the numbered argument variables %1 ... %9 to the left by one (%1 becomes what was %2, etc.)
Added CALL command which will call a routine (label) in the currently executing command file
Added SET VERIFY and SET NOVERIFY commands which enable or disable DO command echoing
Added SET MESSAGE and SET NOMESSAGE commands which globally enable or disable the display of status messages when commands (or Do Commands) return with unsuccessful status
Added SET ON INHERIT and SET ON NOINHERIT to globally enable inheritance of ON state and actions when DO commands are invoked
Added PROCEED and IGNORE commands which are do nothing but return success. These can be used in specific ON actions to possibly ignore particular return status values
Added DO command file line number to error messages which are displayed while processing DO command files
Expanded the DO command nesting level to 20 to potentially allow for more nesting due to the extensive use of CALL commands are used
- Removed flawed logic which assumed that sim_interval was meaningful when referenced by an asynchronous thread.
- Adjust the event_time of events removed from the asynch queue to account for the average time spent on the queue before the event was noticed by the instruction execution thread.
- Added a sim_activate_notbefore function which specifies an rtime which is the earliest time the event should fire.
- Changed the 'wakeup from idle' logic to force an immediate asynch queue check if the wakeup was not due to a timeout (i.e. it was due to an asynch queue insertion).
- Fixed the descrip.mms to build asynchronous support on AXP and IA64 VMS with kernel threads enabled
