With this update, the erase gap operation has been split out of
"sim_tape_wrgap" into a separate, internal "tape_erase_fwd" routine that
is called from "sim_tape_wrgap" as well as from the new "sim_tape_errecf"
routine. There's a corresponding internal "tape_erase_rev" that's called
from the new "sim_tape_errecr" routine.
I've shimmed "sim_tape_rdlntf" and "sim_tape_rdlntr" to move the tape
context and debug stuff out of the routines that I'm maintaining. This
will allow me to replace those functions in their entirety with the
corresponding functions in my development sources for future updates.
It also allows me to keep Bob's version in sync. As my routines are static
and only called once from the shims, compilers should optimize away
the function calls and instead inline the code, so there'd be no extra call
overhead.
I'd also like to keep "tape_erase_fwd" and "tape_erase_rev" untouched for
the same reason. If you wish to add debug calls to "sim_tape_errecf" and
"sim_tape_errecr", that's fine.
The major change is the implementation of deferred IO - a more
accurate implementation of the 1620's "stop in its tracks" IO model.
When a device uses deferred IO, instruction execution is suspended
until the IO completes successfully. Operator interruptions, errors,
and so on do not return to instruction execution; this only occurs if
the IO completes successfully or the command SET CPU RELEASE is given
(equivalent of pressing the RELEASE button). Otherwise, the current IO
operation continues to execute.
Only the console typewriter and paper tape reader/punch currently
implement deferred IO; there are operational issues with those devices
that require more accurate modeling. The card reader/punch, line
printer, and disk still execute IO "instantaneously". It's not all
that hard to convert an instantaneous device to deferred operation,
but there's no point in doing so (and possibly introducing new bugs)
unless there's an actual operational issue. The 1620 doesn't have
overlapped IO, so programs can't tell the difference, by and large.
A number of other issues have been addressed as well, including the
bizarre "treat RM as 0 in the Q field" required by MI-015; the
treatment of non-existent indicators as always off; and various other
tweaks.
I've run CU01 (again), which at least gives typewriter and paper-tape
IO a basic workout; and it works. I leave more detailed testing to
people who know the machine better than I do.
The documentation has been updated to include Tom's detailed breakdown
of IO handling for all IO operations on the typewriter, paper-tape
reader/punch, card reader/punch, and line printer.
- Add support to query remaining usecs on pending events.
- Generalized the sim_interval adjustment in sim_idle to allow more than
a single decrement.
- More overhead reduction when idling.
- Carry usec values as double through out to fully support long wall clock
delays.
commit ef6528bf32 added support for automatic WRU detection for simulators
that don't have a console port, but it was never documented and the addition of
that support potentially interfered with SAVE/RESTORE behavior.
The console connection state is now automatically saved and restored.
The output of remote console commands gets truncated at the configured
buffer size. The default has been raised from 1400 to 8192.
Common remote console usage is from the same host as the simulator and
as such localhost TCP traffic is delivered in chunks at least 8192 so no extra
packets will be involved in transporting the potential extra data and no
transmission delays on the send() call.
The minumum size is now 1400 (which was the prior default).
The RUN command implicitly resets all devices which may have unexpected
consequences for a novice user.
The logic now produces a warning about this side effect when more than one
RUN command is executed in the same simulator session.
An explicit RESET command suppresses this warning for a subsequent RUN
command.
A RUN command with the -Q switch also suppresses this warning.
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.
Add discussion of the recommended handling of instruction history
recording. Also recommendations for read and write breakpoints to
cover cases such as I/O registers.
Also extended the optional VM supplied routines to include sim_vm_sprint_addr.
Simulators which provide sim_vm_fprint_addr should also provide
sim_vm_sprint_addr with sim_vm_fprint_addr reworked to leverage
sim_vm_sprint_addr internally. sim_vm_sprint_addr is currently only used by
sim_brk_message() which is an API which a simulator may choose to use if
it supports multiple breakpoint types,
- Add detailed error message info while parsing breakpoint commands
- Properly limit breakpoint class values to reflect available mask bits
- Declare globally sim_brk_npc since it is a documented API
- Revise simh_breakpoints.doc to reflect current behavior
- This release of the HP 3000 simulator adds the following device simulation:
- 30209A Line Printer Controller with One 2607/13/17/18 Line Printer
The simulation supports the use of custom VFU tape images, as well as the
built-in HP-standard VFU tape. The simulated device name is "LP". The full set
of configurable options is detailed in a new section of the HP 3000 Simulator
User's Guide.
In addition, the preconfigured MPE-V/R disc image has been updated to add the
following features:
- The MPE cold load command files attach the line printer to the "lp.txt"
output file and specify the "-n" option to clear the file before use.
- Preinstalled User-Defined Commands (UDCs) provide access to the COBOL 74
compiler with the MPE-V/E :COBOLII, :COBOLIIPREP, and :COBOLIIGO commands,
and to the COBOL 85 compiler with :COBOLIIX, :COBOLIIXPREP, and :COBOLIIXGO.
However, see the implementation note below.
--------------------
Implementation Notes
--------------------
- MPE requires a line printer, so it is recommended that the MPE startup
simulator command file include an ATTACH LP <filename> command to load paper
into the printer before cold loading. If the printer is not attached, it
will appear to MPE to be out of paper.
- The line printer terminates each print line with an HP-standard CR/LF pair.
If the output file is to be retained as a text file on a Unix system, removal
of the carriage returns, e.g., via the "dos2unix" utility, may be desirable.
- The simulator currently does not provide the HP 32234A COBOL II firmware
instructions, so programs generated by the COBOLII compiler will abort at run
time with an "ILLEGAL INSTRUCTION" error. Programs generated by the COBOL
compiler do not use these instructions and therefore are not affected.
----------
Bugs Fixed
----------
1. PROBLEM: The effective address of a byte pointer with a negative index is
calculated incorrectly.
VERSION: Release 1
OBSERVATION: Defining a :WELCOME message in MPE appears to work, but when
the next logon attempts to print the message, an infinite number of CRLFs
are printed instead.
CAUSE: The welcome message is stored in an extra data segment. The format
for each message line is a line length stored in the lower byte of the word
preceding the message string. The code defines BYTE POINTER NEXTLINE and
points NEXTLINE to the first message character. The line length is set
with NEXTLINE(-1) := IOCOUNT. This generates a LOAD <IOCOUNT> ; LDXN 1 ;
STB <NEXTLINE>,I,X sequence.
In the "cpu_ea" routine, the indexing adds the X register value (-1) to the
byte pointer (NEXTLINE). This causes an overflow that is not masked to 16
bits. For a word access, this displacement is added to the base register
and then masked to 16 bits, which gives the correct value. However, for
byte accesses, the displacement is divided by 2 and then added, and the sum
is masked. Dividing by 2 shifts the overflow bit into the MSB, causing the
addition result to be off by 32K. The STB goes to the wrong location, the
original zero in the length byte location is retained, and when the welcome
message is printed, a zero-length line is printed, and the byte pointer is
incremented by zero, so the null line is printed forever.
RESOLUTION: Modify "cpu_ea" (hp3000_cpu.c) to mask indexed displacements
to 16 bits after adding the X register value.
STATUS: Fixed in Release 2.
2. PROBLEM: An SMSK instruction may clear the interrupt mask flip-flop of a
device that specifies that it is should be "always enabled."
VERSION: Release 1
OBSERVATION: If the TOS word is zero, an SMSK instruction will clear the
interrupt mask flip-flop of a device whose mask jumper is set to "E"
(always enabled).
CAUSE: In response to a DSETMASK signal, device interfaces set their
interrupt mask flip-flops by "anding" the incoming data word with the
interrupt mask jumper setting. The jumper setting value for "always
enabled" is %177777, which sets the mask flip-flop in all cases, except
when the data word is zero.
RESOLUTION: Modify hp3000_atc.c, hp3000_ds.c, and hp3000_ms.c to set their
mask flip-flops unconditionally if the jumper setting is "E".
STATUS: Fixed in Release 2.
3. PROBLEM: The "SET <dev> INTMASK=<n>" command sets the wrong bit in the
device interface's interrupt mask jumper setting.
VERSION: Release 1
OBSERVATION: The interrupt mask jumper on a device interface is set by
specifying the mask bit number in a "SET <dev> INTMASK=<n>" command. This
sets a bit in the device's interrupt mask jumper word corresponding to the
bit number requested. However, the bit numbering is incorrect; setting the
jumper for bit 15, for example, sets bit 0 of the jumper word. Therefore,
the interface's mask flip-flop is not set as expected when an SMSK
instruction is executed.
CAUSE: The bit numbers were counted from the wrong end of the word.
RESOLUTION: Modify "hp_set_dib" and "hp_show_dib" (hp3000_sys.c) to number
the bits from the MSB instead of the LSB.
STATUS: Fixed in Release 2.
4. PROBLEM: The Multiplexer Channel is not generating the ACKSR signal
correctly.
VERSION: Release 1
OBSERVATION: The line printer controller hangs when an SIO chained write
is performed. The first programmed write completes normally, but the
second does not start. The channel is waiting for a service request that
does not occur.
CAUSE: The service request from the last write of the first block transfer
is being cleared by an ACKSR generated by the Multiplexer Channel when it
performs the IOCW fetch in State A for the second write request. The
channel should omit this ACKSR when the previous I/O order was a chained
read or write. However, the simulator is testing the order just fetched
(Write) instead of the order that has just completed (Write Chained).
RESOLUTION: Modify "mpx_service" (hp3000_mpx.c) to test the correct I/O
order in State A.
STATUS: Fixed in Release 2.
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.
Users wanting to build simulators with locally build dependent packages or
packages provided by an unsupported package management system can
override where this procedure looks for include files and/or libraries.
Overrides can be specified by define exported environment variables or
GNU make command line arguments which specify INCLUDES and/or LIBRARIES.
Each of these, if specified, must be the complete list include directories
or library directories that should be used with each element separated by
colons. (i.e. INCLUDES=/usr/include/:/usr/local/include/:...)
Binaries built with unsupported library components will have a 'unsupported' tag
in the output of the SHOW VERSION command.
