Coverity flagged one magtape simulator for having fewer case breakouts
than the range of MTSE_x errors, after they were expanded for
MTSE_LEOT (listed as "V4 compatibility") and MTSE_RUNAWAY (for
Dave Bryan's implementation of erase and erase gap).
According to Dave, it turns out that MTSE_RUNAWAY can only be
returned if the magtape simulator supports and implements a density
specification and the ERASE function. The simulators Bob Supnik wrote
don't meet that criteria, so the expanded errors can't be returned.
Simply add a "default" case to the map logic returning SCPE_IERR for
unexpected cases.
Devices that do single character I/O could be attached to non seekable
host OS devices (tty, pipes, etc.) and thus shouldn't count on fseek()
and ftell(). These DEVICEs on these simulators do single character I/O
and easily can update their POS REGisters to reflect how much data has
been emitted. Changing such a REGister will have no useful effect
when attached to a non seekable file.
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
Problem: Currently when viewing the Nova CPU history the carry flag is always
displayed as 0 regardless of it's actual value at the time.
Cause: The carry bit is stored in bit 17 and is lost when stored into the
int16 carry member of struct Hist_entry
Solution: Shift carry into bit 0 before storing it in the CPU history.
Improve code for displaying carry bit.
This avoids a potential invalid pointer dereference when formatting
the return value from sim_instr() if it is < SCPE_BASE but greater
than the previously defined static array size.sizeof
Update simh.doc to reflect this generic change.
This implements the principle of "least surprise", in that users won't
normally expect to start overwriting an existing file on these devices.
Real hardware didn't behave that way. A new (empty) file can always
be created with the -N switch on the ATTACH.
Most history routines defined a local sim_eval of the proper length, but the
erroneous ones were fixed length machines that defined an integer variable
instead of an integer array of length 1. The VAX used the global sim_eval.
The changes follow the VAX practice.
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.
This reverts commit 5551a0dd9c.
The original idea was that the state being put into simh registers would be required to have all useful information available when remote console executed commands. These steps were taken from the code that sim_instr() executed as it was exiting. After this change was made it was realized that once a remote console command executed it might change state that directly affected instruction execution. To solve this, the logic that executes before the instructions in sim_instr() would then need to be executed whenever the event dispatch processing completed. This approach is messy, burdensome and potentially a lot of overhead for every event dispatch even though almost none of the event dispatches would be for remote console command execution. A completely different approach was suggested by J. David Bryan. That alternative approach would be to have remote console commands execute outside of the sim_instr() routine. Thus allowing the existing prelude and postlude code in sim_instr() to be performed naturally and let the remote console activities run in the same context as all other simh commands. Recent changes to scp and sim_console implement this alternative approach and thus these original changes are completely irrelevant and are thus being removed.
John Kichury revived Startrek II running under DCC Basic which originally ran on the Digital Computer Controls (DCC) D-116 DG Nova clone
This program (or the Basic interpreter) requires console input with even parity.
SET TTI EVEN
will now enable that.
