Take the version of the code from VAX/vax4nn_stddev.c and vax4xx_stddev.c,
and apply it to 730, 750, 780, 820 and 860.
If we can assume that clk_tps always remains 100, this can be simplified
further.
Historically this functionality was reimplemented within each
DEVICE simulator often with slightly different implementations
and inconsistencies. Solving this globally within SCP required
changes in many places, but should henceforth be reasonably
managed.
As discussed in #1034
- Only if backing store is used (i.e. OS Agnostic mode)
- Previously this was only done on a clean simulator exit. That could
result in inconsistent timing information in operating system images vs
the saved TODR baseline data
- Always return TODR values rounded to the TODR granularity (10ms).
Programmatic interval timers are not proper candidates for calibrated
clocks since the interval values can change arbitrarily under program
control and then interfer with attempts at proper calibration.
Add consistent debug options to track TODR activities and the values which
are set. Debug data will display the VMS time related to the values set and
read.
Clock ticks for these simulatrs are performed by programmatic setup of the
interval timer device (TMR) and have nothing to do with the TODR which
increments at 100Hz, but doesn't generate ticks to the simulated system.
Removing pseudo ticking of the TODR improves simulator behavior
when idling. As previously implement, the timing of the TODR and TMR
ticks weren't aligned and and idle simulator would have to wake up to
service both tick activities.
The real hardware has a TODR which changes every 10ms to reflect changes
to wall clock time. This is already completely achieved by referencing the
host system time whenever the TODR register is referenced. No need for
to simulate pseudo ticking.
The real interval timer hardware generates ticks a the rate specifically
programmed in the interval timer device registers. The common cases
programmed the ticks at 10 ms intervals (100Hz), but real operating systems
exist which programmed ticks at 16667 usecs (60Hz).
When the TODR device (CLK) is attached to a state file, it operates in OS
agnostic mode. This file can now be ported between hosts with different
endianness and work consistently to track the time of year.
Additionally, the VAX and VAX750 TODR values now properly don't
progress when they have zero values (or when they overflow back to zero).
Asynchronous clocks are now built for all simulators which are built with
SIM_ASYNCH_IO defined. The default behavior has asynchronous clocks
disabled since this is still experimental, but it can be enabled with
SET TIMER ASYNC.
Catchup clock ticks are now available, but since they're experimental,
they aren't enabled by default. Catchup ticks are only available if the
simulators clock device calls sim_rtcn_tick_ack to acknowledge processing
of clock ticks. The VAX simulators have been modified to leverage this.
Catchup clock ticks can be enabled with SET TIMER CATCHUP
Additionally, an idle threshold is provided which can be used to
influence when clock calibration may be suppressed. The default is not
to suppress calibration activities.
The various timer behaviors are visible with the SHOW TIMER command.
The state of the operating timer facilities is visible with: SHOW CLOCK
Timer events which are queued are visible with the SHOW QUEUE command.
- Previous changes made to support 32V's 60HZ clock tick introduced changes
which didn't properly handle increments and interrupt generation while single
stepping the timer.
- The icr_rd routine returned an incorrect value when interpolation was
necessary due to a missing cast when converting from double to uint32.
- Properly start the timer from the current state of the interval count register
when the timer was previously stopped.
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.
The original implementation coupled the elapsed time measurement
to the 100Hz internal calibration clock. This worked well enough for very
long intervals but not well at all for any intervals less than 50ms. The net
result is that it couldn't usefully be used to produce the 60Hz clock ticks
which Unix 32V used it for. It now leverages the microsecond timing
provided by sim_activate_after(). This problem is reported in #253
This is necessary to avoid kernel type ahead buffer overruns when a user
pastes a chunk of data into a console session as described in issue #246
Other console input speeds can be set with SET CONSOLE SPEED=nnn
Fixed auto configure bugs which didn't allow Fixed CSR Addresses or Fixed Vectors to be set using the auto configure information.
Fixed display of address and vectors to indicate that the assigned address and/or vector is in the floating set.
Added extended definitions to the auto configure table to reflect all known potential static and floating and static addresses as of VMS V5.5-2
Changed the name of the VAX 11/780 console floppy device name to RXC from RX (which collides with a Unibus name for the RX11).
