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J. David Bryan 0e119d70bb HP2100: Release 30
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SIMH/HP 2100 RELEASE NOTES
================================
J. David Bryan <jdbryan@acm.org>
Last update: 2020-11-07
This file documents the release history of the simulator for the Hewlett-Packard
2114, 2115, 2116, 2100, 1000-M, 1000-E, and 1000-F machines.
The home page for the HP simulators is:
http://simh.trailing-edge.com/hp/
An HP 2100 "release" is made when one or more major changes have been
incorporated. Each release is documented below and describes the changes (new
features and corrected errors) that have occurred since the prior release. A
revised "HP 2100 Simulator User's Guide" accompanies every release where
user-visible changes were made.
A "release update" is made to fix minor errors that do not affect normal user
operation. Examples of updates might be expansion or correction of source file
comments, minor algorithm improvements, or rewording of error messages. Updates
are not documented here, although every change is reported in the change logs
that appear at the beginning of all HP 2100 source files.
The HP simulators were previously associated with the "SIMH 4.0" project here:
https://github.com/simh/simh
...but are no longer. Any simulator reporting itself as "V4.x" is not
authorized and not supported by your HP maintainer. Regression testing with the
original HP diagnostics suites is performed only on the simulators available
from the trailing-edge site. See the notes below for more information on this
transition.
===============================
Reporting Bugs in the Simulator
===============================
If you find a bug in the HP 2100 simulator, please report it directly to your HP
maintainer at the address shown at the top of these notes. Please attach a
console log that shows the simulator version and contains a reproducible test
case that illustrates the problem. See the SET CONSOLE LOG command in the
"Console Options" section of the "SIMH Users' Guide" for details on how to
enable logging and the SHOW VERSION command in the "Displaying Parameters and
Status" section.
=============================
The 4.x to 3.x SCP Transition
=============================
Internally, a SIMH simulator consists of a "front end," designated the Simulator
Control Program (SCP), and a "back end" that provides the machine-specific
personality. SCP provides the simulator prompt, console commands such as ATTACH
and RUN, and common library modules for magnetic tape, terminal, and other
device support. SCP manages command file execution, cooperates with the back
end to configure the CPU and I/O devices, and relinquishes control to the back
end to execute machine instructions when a RUN, GO, or CONTINUE command is
entered.
The SIMH project was created and led by Bob Supnik through SCP version 3.9.
Mark Pizzolato then assumed stewardship and substantially extended SCP for
version 4.0. Recently, Bob has produced SCP version 3.10, which adopts some,
but not all, of the new features provided with version 4.0. It also has a
markedly simpler internal structure compared to 4.0.
The HP 2100 simulator had been migrated from SCP 3.9 to 4.0, but the rapid
development cycle and greatly increased complexity introduced a number of errors
and incompatibilities that made it very difficult to ensure stable HP simulator
operation. Regression testing became problematic; often the SCP would change
between simulator testing and code release. This has led to an untenable
support situation.
Therefore, starting with Release 29, the simulator has been retargeted to SCP
3.10 and its successors, which will be used for all future releases. This does
not affect machine execution, i.e., once a RUN or GO command is given, but it
does have consequences for user-written command files, as SCP 3.10 does not
implement all of the new-for-4.0 commands.
The HP simulators provide a superset of the SCP 3.10 commands. These are
documented in the "SIMH Users' Guide Supplement" that is provided in PDF format
in the "doc" subdirectory of the distribution archive. Those with existing
user-written command files should consult this document for the ramifications of
the SCP transition.
===================
General Information
===================
The simulator passes the HP 24396 offline diagnostic suite with some expected
failures due to unimplemented features. For example, the disc diagnostic
error-correction logic tests and the tape diagnostic CRCC and LRCC tests fail,
as these features are not supported. However, all features that are required
for operation of the supported HP operating systems pass their respective
diagnostic tests. See the accompanying "hp2100_diag.txt" file for details.
The simulator has been tested with the following operating systems:
- SIO, BCS, and MTS.
- 2000E, 2000F, and 2000 Access Time-Shared BASIC.
- DOS, DOS-M, and DOS-III.
- RTE, RTE-B, RTE-C, RTE-II, RTE-III, RTE-IV, RTE-IVB, and RTE-6/VM.
The user's manual for the simulator is provided in PDF format in the "doc"
subdirectory of the distribution archive.
For those intending to run 2000F or 2000/Access Time-Shared BASIC, a monograph
entitled "Running HP 2000 Time-Shared BASIC on SIMH" is available from the
"Documentation" section of the simulator site listed above. It discusses the
requirements for successful TSB startup and operation and the issues involved in
synchronizing the dual-CPU simulation setup required by TSB. TSB has run
successfully on SIMH for many years, but the advent of multi-core host machines
has increased the difficulty in getting the two SIMH instances to coordinate
properly. The paper presents some configuration guidelines that improve the
probability of successfully running TSB.
Another paper available from the simulator site is entitled "The Evolution of
the HP 21xx/1000 I/O Simulation" and describes the several I/O simulation
designs that have been employed in the simulator as it has evolved to
accommodate the widening range of I/O device interfaces. It also describes in
detail the current design and its tradeoffs, and serves as a tutorial for those
intending to write their own HP interface simulations.
-----------------------
Compiling the Simulator
-----------------------
Compilation instructions are documented in Section 1 of the "SIMH Users' Guide
Supplement" that is provided in PDF format in the "doc" subdirectory of the
distribution archive.
------------------
Available Software
------------------
Ready-to-run software kits for several of the HP 21xx/1000 operating systems are
available from the "Software Kits" section of the simulator site listed above.
Each kit contains a bootable disc or tape image and associated command files
that automate the system startup process. Command files to perform new system
generations are also included. Refer to the site for details.
The Computer History Museum has graciously arranged with HP to offer the HP 1000
Software Collection with a sublicense for non-commercial use by private
individuals. The Collection is hosted by Bitsavers at:
http://www.bitsavers.org/bits/HP/HP_1000_software_collection/
QCTerm, a free HP 700 terminal emulator for Microsoft Windows, is available from
the HP Computer Museum at:
http://www.hpmuseum.net/display_item.php?sw=585
Use of an HP terminal via a serial port or an HP terminal emulator via Telnet
enables more advanced screen editing features of the RTE operating systems.
Generic Telnet clients generally will work, albeit with reduced functionality.
Manuals describing the operation of HP software are available from Bitsavers at:
http://www.bitsavers.org/pdf/hp/1000/
http://www.bitsavers.org/pdf/hp/2000TSB/
http://www.bitsavers.org/pdf/hp/21xx/
...and from the HP Computer Museum at:
http://www.hpmuseum.net/collection_document.php#CS
----------------
Year 2000 Issues
----------------
RTE-6/VM Revision 6200 is Y2K compliant, except for the READR and SAVER
programs. The errors are cosmetic only.
RTE-IVB Revision 5010 is not Y2K compliant. All of the failures are in
subsystems; the operating itself (time-of-day clock) accommodates dates through
2059. All of the errors are cosmetic. Typically, punctuation characters appear
in the years, e.g., "19:0" for 2000.
All other HP operating systems are not Y2K compliant. For these, the system
time should be set to a corresponding year in the 20th century. Refer to the
"Variable Substitution" section of the "SIMH Users' Guide Supplement" for
details on using the %DATE_RRRR% and %DATE_RR% substitution variables on
non-Y2K-compliant systems.
-----------------------------
Bugs in RTE-IVB Revision 5010
-----------------------------
Testing during simulator development revealed the presence of a bug in RTE-IVB
Revision 5010:
- The $BALC module in the system library has a bug that causes memory
corruption. This module is used by the ACCTS program and manifests itself by
printing gibberish after the "PLEASE LOG ON:" prompt.
Specifically, the internal MXEV routine performs a cross-store indirect via a
location in Table Area II (XSA $MAXI+0,I). This fails because the indirect
chain is resolved in the user map, but TA II is not present in the user map
of large-background programs, such as ACCTS. Therefore, the location in the
user map corresponding to $MAXI in the system map is used as the pointer to
the location to store.
A workaround is to load the ACCTS program as a regular background program
instead of as a large background program. Regular background programs
include Table Area II in the user map. Note that ACCTS requires SSGA access,
so use "OP,BGSS" for online loading or specify "ACCTS,19,90" in the Parameter
Input Phase of a system generation.
======================
Release 30, 2020-11-07
======================
This release of the HP 2100 simulator adds the following features:
- A new concurrent-mode FLUSH command has been added to flush terminal logs and
attached device files that otherwise would be flushed only when the simulator
is stopped. This allows external examination of these files while the
simulator continues to run.
- Terminal multiplexer line logs are now flushed each time the simulator stops.
Prior to this, closing and then reopening a line log was the only way to post
buffered writes to disc.
- The -N (new file) option has been added to the SET BACI LOG, SET MPX LOG, and
SET MUXL LOG commands to create new, blank log files. Without the option,
the commands will append to existing log files.
- The HP 12972C 8-channel terminal multiplexer (MPX) and 12920A 16-channel
terminal multiplexer (MUX) now allow channels to be omitted from the
connection order. For example, a SET MPX LINEORDER=0-3 command permits
connections to channels 0 through 3. Additional Telnet connection attempts
will be rejected with an "All connections busy" message, and attempting to
attach a serial port to a line not in the connection order will be rejected
with a "Unit not attachable" message.
- A new INTERLOCK option has been added to the IPL device. This provides a
more precise way of synchronizing the two simulator processes running the HP
2000 Time-Shared BASIC operating system. Entering a SET IPL INTERLOCK=<n>
command restricts each process to executing <n> machine instructions before
performing a rendezvous with the other process. In this way, both processes
remain in approximate lock-step, which substantially improves system startup
reliability, even when one process is preempted during initialization by the
host operating system. An associated SHOW IPL INTERLOCK command displays the
current interlock value.
- The IPL device now works on FreeBSD and Cygwin host platforms, as well as the
Windows and Linux platforms that were previously supported.
- A new -E switch has been added to the ATTACH IPL command. This enables
falling back to timed waits if the host platform does not support the
synchronization routines necessary for the SET IPL WAIT and SET IPL SIGNAL
commands.
- The CMD trace option for the IPL device now decodes and reports all TSB
commands that pass between the System Processor and the I/O Processor.
- The PSERV and STATE trace options have been added to the IPLO device.
Enabling the PSERV option traces the periodic calls to the new process
synchronizer. Enabling the STATE option traces calls to the host platform
event routines, as well as internal synchronizer states during rendezvous.
--------------------
Implementation Notes
--------------------
- The terminal multiplexer LINEORDER option now omits unspecified lines from
the connection order. Prior versions appended unspecified lines to the end
of the specified order. To obtain the prior behavior, append the keyword ALL
as the last parameter to the connection order list.
- New releases of the HP 2000F and 2000 Access software kits use the SET IPL
INTERLOCK command instead of the prior SET IPL WAIT/SIGNAL commands to
synchronize the two simulator instances and provide more reliable system
startup under a wider variety of host system conditions.
- The 2000 Access software kit now includes a command file to run the
program that converts files between Access and 2000 C/F systems.
- The "Running HP 2000 Time-Shared BASIC on SIMH" monograph has been
extensively revised to cover the application of the new SET IPL INTERLOCK
command to the TSB startup command files.
- The previous method of sleeping for a few milliseconds during 2000 Access
startup to avoid IOP initialization errors is no longer required when the
new IPL interlock is used. The capability has been retained, however, and
will be used if the host platform does not support synchronization events.
- The size of the shared memory area that simulates the processor
interconnection cables of the IPL device has been changed. On Linux and
macOS systems, this area is implemented by a file named "HP 2100-MEM-<code>",
where <code> is he code number supplied to the ATTACH IPL command. The file
is located in the "/dev/shm" directory. If the file is present, it must be
removed before running the simulator, or a "File open error" will result when
an ATTACH IPL is attempted. The new release of the simulator removes the
file automatically when a DETACH IPL is performed, so manual removal must be
done only once.
----------
Bugs Fixed
----------
1. PROBLEM: Breakpoint actions after an included true IF are discarded.
VERSION: Release 29.
OBSERVATION: If a breakpoint has actions that include an IF command
followed by additional actions, and the IF command evaluates to TRUE, then
the IF actions executed, but the remaining breakpoint actions are
discarded. For example:
sim> set environment X=0
sim> break 10 ; if "%X%" == "0" echo X is 0 ; echo Done
sim> go
One would expect to see:
Breakpoint, P: 00010 (NOP)
sim> if "0" == "0" echo X is 0
sim> echo X is 0
X is 0
sim> echo Done
Done
sim>
Instead, only the first ECHO is performed. The second one is discarded.
However, execution is correct if the IF condition is false:
sim> set environment X=1
sim> break 10 ; if "%X%" == "0" echo X is 0 ; echo Done
sim> go
Breakpoint, P: 00010 (NOP)
sim> if "1" == "0" echo X is 0
sim> echo Done
Done
sim>
CAUSE: IF actions are executed by setting the breakpoint action pointer to
the action list and returning to the command loop. While the IF command is
executing, the pointer is pointing at the "echo Done" part of the
breakpoint action list. However, if the IF condition is true, the pointer
is changed to point at the "echo X is 0" command, and the remaining
breakpoint actions are lost.
RESOLUTION: Modify "if_cmd" (sim_extension.c) to append the remaining
breakpoint actions to the actions specified by the IF command, so that the
former are not lost.
STATUS: Fixed in Release 30.
2. PROBLEM: Linking with recent compilers results in duplicate symbol errors.
VERSION: Releases 29.
OBSERVATION: If the simulator is compiled with a recent compiler version,
the link step fails with duplicate symbol errors. The symbols reported are
"sim_vm_release", "vm_sim_vm_init", "vm_console_input_unit", and
"vm_console_output_unit".
CAUSE: The VM hook extension mechanism is implemented with "tentative
definitions" of the hook variables. The C standard says:
"If a translation unit contains one or more tentative definitions for an
identifier, and the translation unit contains no external definition for
that identifier, then the behavior is exactly as if the translation unit
contains a file scope declaration of that identifier, with the composite
type as of the end of the translation unit, with an initializer equal to
0."
This behavior is such that if no module contains a definition with an
initializer, the hook will have a zero value. However, if a module
contains a definition with an initializer, the hook is assigned that value.
This allows hooks to be set without changing the hook's tentative
definition simply by including a VM module that declares it with an
initializer.
This mechanism relies on the linker to resolve the multiple definitions of
a given hook to a single reference. For this to occur, the compiler must
mark tentative definitions as "common" allocations, e.g., with the
"-fcommon" option to gcc. Traditionally, gcc (and clang, etc.) defaults to
common allocations for tentative definitions. However, the gcc manual
claims that, "This behavior is not required by ISO C, and on some targets
may carry a speed or code size penalty on variable references."
Newer versions (starting with gcc 10) default to data allocations instead
("-fno-common"), and multiple tentative definitions now result in duplicate
symbol errors rather than merged accesses.
RESOLUTION: Modify sim_extension.h to declare "vm_sim_vm_init" only if the
USE_VM_INIT symbol is defined. Modify "ex_initialize" (sim_extension.c) to
remove the tentative definition and to make the external "vm_sim_vm_init"
call conditional on USE_VM_INIT. Modify "one_time_init" (hp2100_sys.c) to
set the "sim_vm_release" hook directly. Modify "tty_reset" (hp2100_tty.c)
to set the console unit hooks directly. This removes all tentative
definitions from the simulators.
STATUS: Fixed in Releases 30.
3. PROBLEM: Trace output to stdout on Unix results in stair-step output.
VERSION: Release 29.
OBSERVATION: Directing the trace output to "stdout" on a Unix system
results in lines stair-stepping across the screen. For example:
sim> set console debug=stdout
sim> set cpu debug=instr
sim> step 2
...produces this output:
>>CPU instr: - 0000 00000 000000 NOP
>>CPU instr: - 0000 00001 000000 NOP
CAUSE: Trace statements are output with LF ('\n') line ends and depend on
host-system translation to the proper line-end convention when the lines
are written to the trace log. However, while the simulator is executing
instructions, the console is placed in "raw" mode so that output
translation, which would interfere with the output from the target
operating system, is not done. As there are no carriage returns in the
trace output stream when writing to stdout, the console cursor simply drops
in place to the next line, so that each line begins at the same column
where the previous line ended.
RESOLUTION: Modify "hp_trace" (hp2100_sys.c) to convert a terminating LF
to a CR LF sequence if output is to stdout. Also modify "sim_instr"
(hp2100_cpu.c) to add CR characters to the stdout stream where line
termination is done explicitly.
STATUS: Fixed in Release 30.
4. PROBLEM: The trace line for an I/O error simulation stop is incomplete.
VERSION: Release 29.
OBSERVATION: With simulation stops on I/O errors enabled, a CPU trace
correctly records the stop, but the stop description is incomplete. For
example:
sim> set ipl enabled
sim> attach -s ipl 1
sim> set cpu stop=ioerr
sim> set cpu debug=instr
sim> set console debug=stdout
sim> go
...produces trace output that ends with:
>>CPU instr: - 0000 00061 000000 simulation stop: Cable not connected to
...while the simulation console reports the full message, "Cable not
connected to the IPLI device."
CAUSE: The trace statement printer for the stop calls "sim_error_text" to
obtain the description of the stop status, but that routine does not handle
VM-specific additions. Upon returning to SCP, the "run_cmd" routine prints
the "sim_error_text" but then calls a VM-specified "sim_vm_fprint_stopped"
routine to handle additions to VM stops.
RESOLUTION: Modify "sim_instr" (hp2100_cpu.c) to call the VM-specific
simulation stop handler via the "sim_vm_fprint_stopped" hook if an I/O
error stop occurred.
STATUS: Fixed in Release 30.
5. PROBLEM: ATTACH/DETACH MUXL <network-port> succeeds but should not.
VERSION: Release 29.
OBSERVATION: The HP 12920A multiplexer simulator defines two devices: the
MUX device that contains the polling unit, and the MUXL device that
contains the terminal line units. The poll unit is attached with the:
ATTACH MUX <network-port>
...command. Line units are attached to serial ports with the:
ATTACH MUXL <serial-port>
...command. These behave as expected. However, the:
ATTACH MUXL <network-port>
...command succeeds but attaches the port to the MUX device. This is
incorrect and should be prohibited.
CAUSE: The "muxl_attach" routine passes a poll unit pointer to the
"tmxr_attach_unit" routine. The latter routine attaches the poll unit
instead of the passed line unit when a device is referenced. However, the
poll unit belongs to a different device, and so the mux line routine
attaches the port to the mux poll device.
RESOLUTION: Modify "muxl_attach" and "muxl_detach" (hp2100_mux.c) to pass
NULL for the poll unit in the "tmxr_attach_unit" calls. Modify the
"ex_tmxr_attach_unit" and "ex_tmxr_detach_unit" routines (sim_extension.c)
to reject the call if a device was referenced and a NULL poll unit pointer
was passed.
STATUS: Fixed in Release 30.
======================
Release 29, 2020-02-15
======================
This release of the HP 2100 simulator adds the following features:
- A new CONCURRENT option has been added to the SET CONSOLE command. Entering
CTRL+E with concurrent mode enabled allows the simulator to continue to run
while presenting an "scp>" prompt for command entry. This permits SCP
commands, such as an ATTACH of a magnetic tape image, to be performed without
causing the simulated system clock to lose time and without disturbing
command file execution.
Concurrent mode is enabled by default. If the prior mode where CTRL+E stops
the simulator is desired, a SET CONSOLE NOCONCURRENT command may be placed in
the "simh.ini" global initialization file that is read automatically at
startup. See the "SIMH Users' Guide Supplement" for details.
- The 12731A Memory Expansion Module has been separated from the CPU simulator
and assigned to its own device ("MEM"). The MEM registers are now displayed
and altered with the EXAMINE MEM <reg> and DEPOSIT MEM <reg> commands and
have been renamed, with the map registers separated into the four functional
sets. Enabling and disabling the device is performed indirectly by the SET
CPU DMS and SET CPU NODMS firmware-installation commands, rather than by the
typical SET MEM ENABLED/DISABLED commands. The CPU feature table in Section
3.1 of the HP2100 User's Guide has been corrected to show that the MEM is an
option for the 1000 M/E/F-Series machines, and 1000 systems without memory
expansion may be simulated by disabling the DMS instruction set.
- Two instances of the 12566B Microcircuit Interface have been added; the
device designations are MC1 and MC2. These devices simulate only the
interface cards and do not have attached peripherals. They are intended as
interrupt and data loopback targets for several HP diagnostic programs and,
as such, are disabled by default.
- An internal "Keyboard Poll" unit has been added to coordinate keyboard input
polling. This unit will be visible in the SHOW QUEUE display.
- The TTY device may now be disabled, as its input poll coordination
responsibilities have been transferred to the internal keyboard poll unit.
This permits correct I/O configuration for systems that do not use a keyboard
device (e.g., the I/O Processor in an HP 2000 Time-Shared BASIC system) or
for RTE systems that use the BACI as the system console device. Previously,
the TTY device would have remained enabled but been assigned a high select
code "out of the way" of the correctly configured set of I/O devices.
- A new SHOW CPU IOCAGE command has been added to display the set of I/O device
interfaces currently installed in the CPU card cage. The devices appear in
select code order, beginning with select code 10 and ending with the last
occupied select code. This makes checking select code assignments and
identifying conflicts much easier than using the SHOW DEVICES command.
- The SHOW CPU ROMS command has been extended to add descriptions of the
bootstrap loader ROMs installed in HP 1000 CPUs.
- The list of the simulated devices displayed by the SHOW DEVICES command has
been rearranged to this order: CPU, CPU devices, and I/O devices
alphabetically. The prior order was essentially random, making it difficult
to locate specific devices.
- New SET <dev> REALTIME and SET <dev> FASTTIME commands have been added to the
TTY, PTR, and PTP devices. The optimized timing values used may be altered
via the corresponding register interfaces.
- The SET PTR DIAGNOSTIC command has been enhanced to provide a second
diagnostic mode. If a paper tape image file is not attached, then the new
mode simulates the installation of a loopback connector in place of the
reader cable, permitting the General Purpose Register Diagnostic to test the
interface. If a file is attached, then the existing mode converts the
attached paper tape image into a continuous loop by logically joining the
ends of the tape, which is needed by the High-Speed Tape Reader/Punch
Diagnostic.
- The new SET PTR REWIND command repositions the attached tape image to the
beginning, so that the tape may be re-read. This is helpful, for instance,
when re-running and specifying different output options to a program that
takes its input from the paper tape reader.
- The new SET PTP DIAGNOSTIC command installs a loopback connector in place of
the paper tape punch cable to run the General Purpose Register Diagnostic on
the interface. The new SET PTP PUNCH command reinstalls the punch cable and
restores normal punch operation.
- Configurable debug tracing has been added to the TTY, PTR, and PTP devices.
- All I/O devices that had not supported debug tracing previously now provide
an IOBUS option to trace data and signals sent and received across the I/O
backplane bus. All peripheral devices now support at least minimal tracing.
--------------------
Implementation Notes
--------------------
- The change from SCP 4.0 to 3.x may affect user-written command files. Be
sure to review Section 3, "SCP 4.x-to-3.x Conversion," of the "SIMH Users'
Guide Supplement."
- The DO command now executes more quietly by default. Specifically, the
"Breakpoint" and "Step expired" messages that normally result from BREAK, GO
UNTIL, and STEP command completions are suppressed, as are the informational
messages from ATTACH and DETACH, such as "Creating new file." This provides
a cleaner console display log when automated prompts and responses are used.
Adding the -A switch to the DO invocation will restore the previous noisier
behavior. See the "DO Command" section of the Supplement for details.
- The SHOW CPU ROMS command is now rejected if the CPU is not a 1000.
- The ION and ION_DEFER CPU registers have been renamed to INTSYS and INTEN,
respectively, to match the names used in the HP engineering documentation.
Note that the sense of INTEN is now reversed: a value of 0 indicates that
interrupts are not enabled (i.e., are deferred), while 1 indicates that
interrupts are enabled (not deferred).
- The TTY KTIME register has been removed. This register was intended to allow
the user to set the keyboard polling interval, but it never worked; instead,
the keyboard poll rate was (and is) always fixed at 100 Hz.
- The TTY TTIME register had been described as the "Time from I/O initiation to
interrupt" but it actually sets the optimized (FASTTIME) time for Teletype
print/punch operations.
- The prior method of rewinding a paper tape by doing DEPOSIT PTR POS 0 does
not work if the console is in concurrent mode. Use the new SET PTR REWIND
command instead.
- The I/O system simulation has been rewritten to model the actual hardware
more closely. This has no user-visible impact, except that IOBUS tracing now
accurately reflects the hardware I/O bus signals. For example, the PRH and
PRL signals now appear in IOBUS traces and show the I/O priority settings.
Any user-written device interfaces will have to be changed to use the new I/O
structure; the Microcircuit Interface in hp2100_mc.c is a simple example that
may be used as a model for the changes needed.
- The hp2100_stddev.c source file has been split into hp2100_pt.c (PTR and
PTP), hp2100_tty.c (TTY) and hp2100_tbg.c (TBG).
- hp2100_cpu.c has been split into hp2100_cpu.c (CPU and I/O), hp2100_mem.c
(main memory, MP, and MEM), and hp2100_dma.c (DMA1 and DMA2). A new
hp2100_cpu_dmm.h file contains the interface declarations for these three
modules.
- hp2100_fp.c and hp2100_fp1.c have been renamed to hp2100_cpu_fp.c and
hp2100_cpu_fpp.c, respectively, and hp2100_fp.h and hp2100_fp1.h have been
combined into hp2100_cpu_fp.h.
- hp2100_cpu1.h has been retired; its declarations have been moved into
hp2100_cpu.h.
----------
Bugs Fixed
----------
1. PROBLEM: The multiplexer upper data card status trace is incorrect.
VERSION: Release 28.
OBSERVATION: Tracing status on the upper data card of the 12920A
Asynchronous Multiplexer Interface with the SET MUX DEBUG=CSRW command
produces incorrect results. For example:
>>MUX csrw: Status is channel 17 | seeking | breaklost | receive
>>MUX iobus: Returned data 042012 with signals (none)
Given the status word 042012 octal, the correct status interpretation is
"channel 17 | diagnose | lost | receive".
CAUSE: A comma is missing after the "break" string constant in the
"upper_status_names" array initializer. This causes the "break" and "lost"
strings to be concatenated and used for bit 1. As a result, the "diagnose"
and "seeking" strings are used for bits 2 and 14 instead of 3 and 15.
RESOLUTION: Modify the "upper_status_names" initializer (hp2100_mux.c) to
use the correct set of status names.
STATUS: Fixed in Release 29.
2. PROBLEM: Tracing the $MPV instruction prints the wrong mnemonic.
VERSION: Release 28.
OBSERVATION: Tracing memory protect interrupts on an RTE-6/VM system
displays the trap cell instruction mnemonic as "ostst" (the firmware test
instruction):
>>CPU instr: U 0170 26072 000005 interrupt
>>CPU fetch: S 0000 00005 105355 instruction fetch
>>CPU instr: S 0000 00005 105355 ostst
>>CPU opnd: * **** 26072 105355 entry is for a memory protect violation
...instead of the expected "$MPV" (memory protect violation instruction):
>>CPU instr: U 0170 26072 000005 interrupt
>>CPU fetch: S 0000 00005 105355 instruction fetch
>>CPU instr: S 0000 00005 105355 $MPV
>>CPU opnd: * **** 26072 105355 entry is for a memory protect violation
CAUSE: The RTE-6/VM OS firmware designates four instruction opcodes as
"dual-use." Opcodes 105354-105357 take different actions, depending on
whether or not they are executed from a trap cell during an interrupt. The
routine that formats these instructions for trace output determines the
mnemonic table to use by the address in which the instruction is stored.
The address value is also used to communicate to the "fprint_instruction"
routine whether or not the value array containing the instruction word(s)
has been loaded. For a CPU instruction trace, only the first word of the
array is loaded (as part of the instruction fetch), so the address value
has an upper bit set to indicate this condition. However, the trap cell
check is not masking this bit off, so instructions executing from trap
cells are treated as though they are executing from high memory.
RESOLUTION: Modify "fprint_cpu" (hp2100_sys.c) to mask the target address
before checking the location when printing "dual-use" instructions.
STATUS: Fixed in Release 29.
3. PROBLEM: DIAGNOSTIC mode of the 12653A Line Printer Interface is not
modeled correctly.
VERSION: Release 28.
OBSERVATION: The 12653A Line Printer Interface used with the HP 2767A line
printer (LPS device) is a modified 12566B Microcircuit Interface. Setting
the card for DIAGNOSTIC mode simulates the installation of an HP 1251-0332
diagnostic test (loopback) connector in place of the printer cable and the
alteration of the jumper configurations to match those required by the
diagnostics that target this interface.
When the Direct Memory Access Diagnostic for the 2115/2116 computer (DSN
101105) was first run, Test 17, which tests character unpacking during
output, failed. It was originally thought that the 12578A DMA card for the
2115 and 2116 had a one-cycle startup latency that did not exist in the
12607B, 12895A, and 12897B DMA cards for the 2114, 2100, and 1000-series
CPUs. This latency was added to the simulation in version 3.7-0, and the
diagnostic passed.
Sometime later, the schematic for the 12578A card was studied more closely,
revealing that the first DMA cycle occurred immediately upon activation
when SRQ (Service Request) was already asserted, as it was in the
diagnostic, so the latency counter was removed. In its place, the LPS
device was modified to change SRQ assertion timing for 211x CPUs.
With the loopback connector in place, asserting STC caused the flag to set
and SRQ to assert after a delay of one instruction. The 12578A diagnostic
required different jumper settings on the 12653A card than were used by the
other diagnostics, and it was assumed that this caused the card to assert
SRQ after a delay of two instructions. These changes were made in version
3.9-0.
A copy of the 12653A interface manual was obtained recently, and studying
the schematic revealed that the unusual jumper settings still resulted in
SRQ assertion after a one-instruction delay. Restoring the simulation to
the correct delay caused diagnostic test 17 to fail again.
CAUSE: Timing analysis of the response to DMA cycles on 2115 and 2116
machines shows that the jumper settings employed by the diagnostic suppress
setting of the Flag Buffer flip-flop, so no SRQ assertion occurs. The STC
and CLF signal assertions that start an I/O operation are coincident and
one T-period in duration (200 ns) in all combinations of CPU models and
cycle types EXCEPT when asserted for a 211x DMA cycle, where they are two
T-periods in duration (400 ns) and CLF lags STC by one T-period. With the
DMA diagnostic strapping, the Flag Buffer flip-flop is set by the STC and
then cleared by the lagging CLF in the same DMA cycle. This inhibits SRQ,
so DMA pauses until the diagnostic can examine the DMA state and then issue
a programmed STC/CLF to assert SRQ. This permits test 17 to succeed.
RESOLUTION: Create a new 12566B Microcircuit Interface simulator
(hp2100_mc.c) to implement the three different strapping behaviors required
by the various DMA diagnostics. Simplify "lps_interface" (hp2100_lps.c) to
operate in the manner expected by the General Purpose Register Diagnostic
when the card is in DIAGNOSTIC mode.
STATUS: Fixed in Release 29.
4. PROBLEM: Simulation stops are reported improperly in CPU traces.
VERSION: Release 28.
OBSERVATION: A simulation stop that occurs while CPU tracing is enabled
reports the cause of the stop in the trace log. However, stop reasons
specific to the HP simulator are not reported properly. For example,
tracing a halt instruction reports "simulation stop: Error 5" instead of
"simulation stop: Programmed halt".
CAUSE: The "sim_error_text" routine called to obtain the error translation
does not return simulator-specific messages. Instead, the routine returns
the generic message, "Error <n>", where <n> is the value of the simulator-
specific stop code.
RESOLUTION: Modify the simulation stop trace at the end of the instruction
postlude in "sim_instr" (hp2100_cpu.c) to call "sim_error_text" for SCP
errors and to obtain HP-specific messages from the "sim_stop_messages"
array.
STATUS: Fixed in Release 29.
5. PROBLEM: RTE-IVB FMGR aborts with a DM error during :DL,2 output.
VERSION: Release 28.
OBSERVATION: Entering a DL,2 command at the system console begins listing
the cartridge but then aborts partway through with this error:
DM VIOL = 100377
DM INST = 126313
ABE 0 177777 0
XYO 47252 0 0
DM FMGR 34463
FMGR ABORTED
The system generation log shows that address 34463 is within the "CLOSE"
subroutine. The violating instruction is a JMP 34313,I that attempts to
return from the subroutine. However, the return address is 14054,I (i.e.,
an indirect pointer) that points to 2000,I that points to 77765,I that is
in unmapped memory. This generates a MEM read violation.
CAUSE: The subroutine does a JSB .ENTR at entry to obtain the parameters
and adjust the return address. As this system has the Fast FORTRAN
Processor firmware, the JSB .ENTR is replaced with the .ENTR microcode
instruction. A CPU trace shows that a TTY interrupt is generated after the
JSB 45,I that calls the subroutine. Because JSB,I disables interrupt
recognition, the TTY interrupt is deferred until the next instruction
executes. The .ENTR instruction checks for interrupts when resolving the
address of each supplied subroutine parameter. Consequently, the deferred
TTY interrupt is recognized when the first parameter is resolved, and the
.ENTR instruction exits with the P register set so that the instruction
will be reexecuted when the TTY interrupt handler exits.
However, the return address was updated before the interrupt was
recognized, so reexecution updates the return address a second time. This
results in an incorrect address, which causes the DM abort when the
subroutine attempts to return.
RESOLUTION: Modify the .ENTR handler in "cpu_ffp" (hp2100_cpu3.c) to
update the return address only if the instruction executes to completion.
STATUS: Fixed in Release 29.
6. PROBLEM: The MEM Violation Register is not freezing for a DM error.
VERSION: Release 28.
OBSERVATION: The value that RTE reports for the Memory Expansion Module's
Violation Register during a DM abort does not match the value of the VR
obtained by a CPU trace. For example, a trace may show:
>>CPU instr: U 0167 34464 000005 interrupt
>>CPU reg: - **** ***** ****** MPF 030000, MPV 034463, MES 163454, MEV 100377
...but then:
>>CPU instr: S 0023 47516 101731 RVA
>>CPU fetch: S 0023 47517 000040 instruction fetch
>>CPU reg: - **** 01454 000000 A 160377, B 034463, X 047252, Y 000000, E o I
The value returned by the RVA (Read Violation Register) instruction is not
the same as the MEV (MEM Violation) value reported by the trace.
Consequently, the value reported by RTE as "DM VIOL =" is wrong.
CAUSE: The VR is being changed when it is supposed to be frozen. The MEM
schematic shows that the VR clock is inhibited by -MEV until CTL5 goes low
and then high again. That is, a MEM violation inhibits the VR clock, which
is reenabled when the MP control flip-flop is set (i.e., when MP is
reenabled). With CTL5 low, VR should not update.
RESOLUTION: Modify "dm_violation" (hp2100_mem.c) to inhibit updating the
VR if "mp_mevff" is set or "mp_control" is clear.
STATUS: Fixed in Release 29.
7. PROBLEM: DETACH -F LPT will not detach if the print buffer is not empty.
VERSION: Release 27.
OBSERVATION: The 2607/13/17/18 line printers do not allow the operator to
take the printer offline if unprinted characters remain in the print
buffer. Instead, the request is deferred until printing completes.
The LPT simulator follows this hardware behavior when processing a DETACH
LPT command, which simulates running out of paper. If printing is still
pending or, for the 2607 only, the paper position is not at the
top-of-form, the message "Command not completed" is printed, and the detach
is deferred until a print command empties the print buffer and paper
movement ceases.
A "force" option is provided to detach the printer paper image file
immediately, regardless of the printer condition. DETACH -F LPT works if
the paper position is not at the TOF. However, it does not work if the
print buffer contains unprinted characters; "Command not completed" is
displayed instead.
Entering RESET LPT followed by DETACH LPT works, but the partial print
buffer is discarded rather than flushed to the output file.
CAUSE: The "lp_detach" routine sets TOF status if the -F switch is
specified, but it does not alter the buffer state.
RESOLUTION: Modify "lp_detach" (hp2100_lpt.c) to write a partial line to
the output file before detaching when the -F option is specified.
STATUS: Fixed in Release 29.
8. PROBLEM: BREAK needs an extra keystroke to stop an HP 2000/Access program.
VERSION: 3.7-1
OBSERVATION: According to the "HP 2000/Access BASIC Reference Manual" (HP
22687-90001), pressing the terminal BREAK key halts program execution and
prints STOP on the user's terminal. For example, running this program:
10 FOR I=1 TO 10000
20 PRINT I
30 NEXT I
40 END
...and pressing BREAK during execution does stop the program output.
However, STOP is not printed until another key (any key) is pressed.
Enabling tracing of the multiplexer and the processor interconnect kit
shows that the break is being recognized by the IOP, which then notifies
the SP by sending a "User abort request" command over the interconnect
link. In response, the SP sends "Kill terminal output" and a "User is
being aborted" commands to the IOP, followed by a "Process output string"
command to print STOP on the user's terminal. The IOP begins the output by
sending a SYNC character before the STOP string. When the transmit
interrupt occurs after SYNC transmission, the IOP reads the input data
register from the mux data card. The data value is 0, which the IOP
interprets as another break request. The IOP then sends another "User
abort request" command to the SP, which responds with a "Kill terminal
output" command, and the cycle repeats. Only when a character is pressed
does the input register data change from 0 to a non-zero value, allowing
the abort cycle to finish.
CAUSE: In hardware, the input data register normally holds the character
received from the selected multiplexer channel. This character has been
assembled by a shift register that is designated the "accumulator" from the
bits arriving on the serial input line. After a send operation, the input
data register also stores the value from the accumulator. In this case,
however, the value is that contained in the shift register after all of the
bits of the output character have been shifted out to the serial output
line. As each output character is padded on the left with 1 bits
(representing the serial stop bits) to an 11-bit length, if the character
length is less than 11, at least one 1-bit will remain in the register.
Therefore, when the IOP reads the register during processing of the
transmission interrupt, the value will be non-zero, and the IOP will not
restart BREAK processing.
Under simulation, however, a send operation places the last received
character in the input data register instead of the shifted send character.
As the last received character was zero (for the BREAK key press), the IOP
sees another break request and starts the abort cycle over from the
beginning.
RESOLUTION: Modify "mux_data_int" (hp2100_mux.c) to place the proper value
in the input data register when a send interrupt is requested.
STATUS: Fixed in Release 29.
9. PROBLEM: The parity status reported in the MUX input trace is incorrect.
VERSION: Release 28.
OBSERVATION: The parity bit (bit 15) of the received data word reflects
the computed parity of the data bits: 1 for odd parity and 0 for even
parity. However, when tracing the multiplexer lower (data) card, the
reported parity is incorrect. For example:
>>MUXL csrw: Input data is channel 0 | odd parity | 0003
The data value (3) has even parity, but it is reported as odd.
CAUSE: The trace reporting string is correctly set to report odd parity
for bit 15 set and even parity for bit 15 clear. However, the trace format
structure specifies the starting bit as bit 0 instead of bit 15. So the
report actually reflects the state of bit 0.
RESOLUTION: Modify "lower_input_format" (hp2100_mux.c) to reflect the
correct offset of the parity bit.
STATUS: Fixed in Release 29.
10. PROBLEM: 2000/Access programs may hang during long printer output.
VERSION: Release 28.
OBSERVATION: When printing or punching a large amount of output data, an
Access BASIC program may hang. Output generation stops for no apparent
reason. The only recourse is to press the BREAK key to stop the program.
CAUSE: There is a race condition between the system processor (SP) and the
I/O processor (IOP) during output to non-shareable devices controlled by
the IOP. The race occurs more frequently when a large amount of output is
generated quickly.
The cause is this code in subroutine #IPAL in the SP main program source
(TSB.asm) that is used to send buffered output data to IOP-connected
devices:
LDA ERTMP SEND
IOR ALB REQUEST
JSB SDVRP,I CODE
LDB #IPAL RETRIEVE
INB BUFFER
LDA B,I LENGTH
JSB SDVRP,I SEND TO IOP
SFS CH2 WAIT FOR
JMP *-1 ACKNOWLEDGEMENT
CLF 0
LIA CH2 RETRIEVE RESPONSE
If this "allocate buffer" ("ALB") request is refused by the IOP because all
output buffers are in use, the resulting "no buffer available" response
will cause the SP to issue a "release buffers" command to the IOP and then
suspend the user's program until the IOP sends a "wake up user" command to
indicate buffer availability. When the line printer completes its
operation on the current output buffer, the IOP frees it and then sends the
command to the SP to resume the user's output.
The problem occurs when the line printer completes just as the allocate
buffer request is made. That request sends two words: the ALB request code
and the buffer length. The IOP denies the request but then immediately
follows it with the "wake up user" command to indicate that a buffer is now
available. If the command arrives between the time the SP sends the buffer
length word and the time it picks up the response, the user program will
hang. This occurs because the response causes the SP to set a flag
indicating that the user has been suspended for buffer availability. If
the "wake up user" command arrives before that flag is set, the command is
ignored. So the SP is waiting for the IOP to issue the wake up, but the
IOP has already issued it. This leaves the suspension in force until the
user aborts the program by pressing the BREAK key.
Nominally, only about nine instructions execute between the STC CH2 (within
the SDVRP subroutine) that causes an IOP to accept the buffer length word
and the SFS CH2 (above) that detects that the IOP's acknowledgement has
arrived. However, the SP's interrupt system is on during the above SFS CH2
/ JMP *-1 loop, and the processor interconnect has the highest I/O
interrupt priority. So if, say, a time-base generator interrupt occurs
during the SFS loop, several dozen instructions may be executed before
control returns to the loop. If, during that time, the IOP command
arrives, the resulting higher-priority interrupt is handled before the loop
return, and the command is ignored because the "user is suspended" flag has
not been set.
RESOLUTION: Modify "card_service" (hp2100_ipl.c) to ensure that an IOP
status response is picked up before an IOP command if both are seen during
the same poll and to insert a long delay between these actions.
Note that this is a workaround, and not a solution, as there is no general
way to ensure that the response is read by the SP program before a pending
IOP command is recognized. That's because the SP does not read the
responses of some commands it sends, so simply holding off input card
commands until the output card data register is read will not work.
STATUS: Fixed in Release 29.
11. PROBLEM: RTE-II hangs in DVR31 if a 7900 disc is mounted while running.
VERSION: Release 28.
OBSERVATION: Mounting a peripheral disc, i.e., unit 1-3, while RTE-II is
running causes a hang within DVR31 (the RTE disc driver) when a :MC command
is issued. For example, with a running system, doing:
scp> attach DPC1 scratch.disc
*RU,FMGR
:MC,-10
...causes the system to become unresponsive. The interrupt system is off,
and execution is looping within the STATW subroutine within DVR31.
Examination shows that STA[1] = 040000 (i.e., First Status). The driver
issues a Seek command to unit 0 and then requests unit 1 status again.
Because STA[1] has not changed, execution loops forever.
If STA[1] is manually set to 000000, the driver exits, and RTE resumes
normal operation.
CAUSE: The Status Register on the 13210A interface is implemented in an
unusual way. It consists of a set of D-type flip-flops whose D inputs are
grounded, and whose individual asynchronous presets are tied to the various
controller and currently selected disc drive status lines. The register is
clocked, and therefore cleared synchronously, when any command OTHER than
Status Check is issued. A Status Check command (as well as a Write, Read,
Check Data, or Initialize command) gates the status signals to the preset
inputs. The register is therefore "ones-catching," and one-to-zero
transitions will not be seen by repeated Status Check commands unless some
other command intervenes to clear the register first.
When the selected drive receives a Status Check command, it also asserts
an internal CLEAR STATUS signal. This clears the Attention and First
Status flip-flops on the drive after they are reported to the controller.
When FMGR attempts to mount a newly attached disc image, DVR31 issues a
Status Check command and sees the First Status bit set. The driver checks
to see if the drive had been previously "downed" by a request for the
unattached drive. If not, then it checks to see if a request is currently
pending. If so, it issues (but does not complete) a Seek command, followed
by another Status Check command. The incomplete Seek is necessary to clear
the status register in order to see that First Status has transitioned from
one to zero.
The DP simulator neglected to clear the drive's First Status flip-flop
after a Status Check command. Consequently, First Status was returned for
subsequent Status Check commands, and DVR31 looped internally forever.
RESOLUTION: Modify "dpd_svc" (hp2100_dp.c) to clear First Status as well
as Attention when a Status Check command completes.
STATUS: Fixed in Release 29.
======================
Release 28, 2018-05-23
======================
This release of the HP 2100 simulator adds the following features:
- The IPLI and IPLO devices now use shared memory instead of network sockets to
simulate the 12875A Processor Interconnect kit that is used to communicate
between the System Processor and the I/O Processor of the HP 2000B, C, F, and
Access Time-Shared BASIC operating systems. This change, in addition to a
new, adaptive service scheduling routine, improves data transfer time between
the processes by a factor of 7 to 1.
- Commands have been added to the IPL device to permit synchronization between
the two simulator processes running the HP 2000 Time-Shared BASIC operating
system. This greatly improves system startup reliability and permits the use
of the HP-documented startup procedure of cross-loading the I/O Processor
program from the System Processor.
- The DIAGNOSTIC options of the IPLI and IPLO devices have been reworked to
permit testing with the HP General Register Diagnostic as well as the
Processor Interconnect Cable Diagnostic.
- The DEBUG options of the IPLI and IPLO devices have been expanded.
- The BOOT command now installs the correct binary loader for the CPU model.
For example, BOOT PTR installs and runs the Basic Binary Loader (BBL) if the
CPU is configured as a 2114/15/16 or 2100, or the 12992K Paper Tape Loader
ROM if the CPU is configured as a 1000 M/E/F-Series. Prior releases
installed the HP 1000 loader ROM regardless of the CPU model.
- The LOAD command has been extended to permit copying of internal device boot
loaders into memory. LOAD <dev> is identical to BOOT <dev> except that the
CPU is neither preset nor run. In particular, LOAD CPU is the equivalent of
pressing the IBL button on the HP 1000 front panel.
- The new SET CPU ROMS command permits altering the set of preinstalled boot
loader ROMs for 1000 CPUs. The new SHOW CPU ROMS command displays the
currently installed set.
- The -N (new file) option to the ATTACH command for disc devices now creates a
full-size image file, equivalent to formatting the new disc before use.
--------------------
Implementation Notes
--------------------
- The abbreviated "SET CPU 21MX" command no longer sets the CPU to an E-Series
model (i.e., to a 21MX-E, a.k.a. 1000-E); instead, it configures the CPU as
an original 21MX (a.k.a. 1000-M). If an E-Series configuration is desired,
it must be requested explicitly with the "SET CPU 21MX-E" command.
- The "RESET -P CPU" command no longer restores the BBL to the protected memory
area of 21xx machines. The "LOAD PTR" command may be used to perform this
function.
- The previous behavior of the "ATTACH -N" command for disc devices, i.e.,
creating a new zero-length image file, may be emulated by first deleting the
file and then attaching it without specifying the -N switch. For instance,
the "DELETE <file>" and "ATTACH <unit> <file>" commands produce a new
zero-length file as "ATTACH -N <unit> <file>" did before this change. The
"ATTACH -N" behavior of other devices, e.g., magnetic tape drives and
printers, did not change; a zero-length file is still created.
- With the change to a shared-memory implementation, only a single "ATTACH IPL"
command is required per instance to establish communication. The System
Processor instance issues an "ATTACH -S IPL <code>" command, and the I/O
Processor instance must issue a corresponding "ATTACH -I IPL <code>" command,
where the <code> parameter is a user-selected decimal number that identifies
the instance pair. The prior "ATTACH [-L | -C] [ IPLI | IPLO ] <port>"
commands are deprecated but retained, so that existing command files will
still work. However, they too will use shared memory rather than network
connections. Consequently, the SP and IOP instances are now required to
execute on the same machine, and the <ip-address> option is no longer
supported.
- Multiple consecutive CLC 0 instruction executions now cause only a single CRS
assertion to the I/O devices. Therefore, IOBUS tracing when running HP 2000
Time-Shared BASIC systems no longer generates a pair of trace lines for each
of the 131,072 consecutive CLC 0 executions typically used to initialize the
12920A Asynchronous Multiplexer.
- The 12875A Processor Interconnect section of the HP2100 User's Guide has been
revised to describe the new ATTACH protocol and process synchronization
commands.
- A list of device boot loaders installed for given device/CPU combinations has
been added to the user's guide.
- The "21MX-M" and "21MX-E" CPU options that had been inadvertently omitted
from the last release of the user's guide have been restored.
- The "Running HP 2000 Time-Shared BASIC on SIMH" monograph has been revised to
cover the application of the new process synchronization commands to TSB
startup command files.
- Preconfigured software kits for 2000E, 2000F, and 2000 Access that employ
the new shared memory and process synchronization commands are now available;
see the "Available Software" section above for details.
----------
Bugs Fixed
----------
1. PROBLEM: Serial port output stalls are not handled properly.
VERSION: Release 27.
OBSERVATION: The TTY, BACI, MPX, and MUX devices support I/O via host
serial ports as well as via Telnet connections. While TTY, BACI, and MPX
output via Telnet works correctly, output via serial ports fails. TTY
output drops characters if the serial port stalls. Attempting to output to
the BACI results in "Console Telnet output stall" and a simulator stop.
Output to the MPX results in dropped characters and eventually an "IOPE"
(parity error) message from RTE.
CAUSE: The terminal multiplexer library (sim_tmxr.c, part of the SIMH
framework) had provided a 256-byte output buffer for each line, independent
of the connection type (Telnet or serial). The library was changed to
reduce the serial buffer size to one byte. The BACI and MPX devices are
internally buffered and default to a "FASTTIME" mode that sends the entire
internal buffer to the library output routine. When the routine receives
the second character, it returns SCPE_STALL status to indicate a buffer
overflow. The device simulations did not expect and did not properly
handle this status.
The TTY and MUX devices are not buffered internally and were not affected
by the loss of serial buffering. However, the TTY would drop output
characters if the host serial buffer overflowed.
RESOLUTION: Modify "tto_svc" (hp2100_stddev.c), "baci_term_svc"
(hp2100_baci.c), and "line_service" (hp2100_mpx.c) to handle terminal
multiplexer library buffer overflows properly.
STATUS: Fixed in Release 28.
2. PROBLEM: The PTR device DIAGNOSTIC option shown in the user's guide does
not exist.
VERSION: Release 27.
OBSERVATION: The "HP2100 Simulator User's Guide" says that specifying the
DIAGNOSTIC option for the PTR device "converts the attached paper tape
image into a continuous loop" for use by the paper tape reader diagnostic
program. However, entering a "SET PTR DIAGNOSTIC" command gives a
"Non-existent parameter" error.
CAUSE: The option name specified in the PTR device's modifier table is
"DIAG". It should be "DIAGNOSTIC" to match the option names used in the
other device simulations.
RESOLUTION: Modify "ptr_mod" (hp_stddev.c) to use the correct option name.
STATUS: Fixed in Release 28.
3. PROBLEM: First Status is not cleared properly on the DP device.
VERSION: Release 27.
OBSERVATION: Execution of the RTE-I paper tape bootstrap for the 7900A and
the 2000F loader for the 7900A halts with disc errors. The offending disc
status word is 040001 octal, which denotes First Status and Any Error.
Both programs expect disc status to be clear after an initial Seek and Read
are performed. However, the disc drive and interface manuals state that
First Status is cleared by a Status Check command, which is not being
issued.
CAUSE: Examination of the schematics in the 7900A Disc Drive Operating and
Service Manual (07900-90002 February 1975) and the 13210A Disc Drive
Interface Kit Operating and Service Manual (13210-90003 November 1974)
shows that, contrary to the documentation, First Status is cleared on a
Read, Write, Check Data, or Initialize command, as well as on a Status
Check command. The current DP implementation follows the manual
description rather than the schematics, so it fails to clear First Status
when the initial Read is performed.
RESOLUTION: Modify "dp_goc" (hp2100_dp.c) to clear First Status as well as
Attention when one of the applicable commands is performed.
STATUS: Fixed in Release 28.
4. PROBLEM: 2000F and Access will not boot from a 7900 drive using the BMDL.
VERSION: Release 27.
OBSERVATION: Attempting to boot Time-Shared BASIC from a 7900 using the
Basic Moving-Head Disc Loader for the HP 2100 CPU results in a HLT 1
(unrecoverable disc error) in the TSB loader. Booting the same system with
the 12992A loader ROM for the HP 1000 succeeds.
The BMDL configures DMA for an oversize (~32000 word) transfer and expects
the disc to terminate the operation with End of Cylinder (EOC) status. The
TSB bootstrap successfully loads into memory. When it starts, it issues a
CLC 0,C followed by a Check Status command that is expected to return zero,
i.e., all status bits clear. However, the EOC bit is set, and the
bootstrap halts with a HLT 1.
CAUSE: The "Disc Interface 1 PCA Schematic Diagram" in the HP 13210A Disc
Drive Interface Kit Operating and Service Manual (13210-90003, August 1974)
shows that the CRS signal, which is generated by the CLC 0 instruction,
does not affect the Status Register contents. However, examination of an
actual hardware interface PCA shows that CRS assertion does clear the
register.
RESOLUTION: Modify "dpcio" (hp2100_dp.c) to clear the status register on
receipt of a CRS signal. Note that later versions of the service manual
(May 1975 and May 1978) show the correct CRS connection.
STATUS: Fixed in Release 28.
5. PROBLEM: Forcibly disconnected 2000E multiplexer ports are unresponsive.
VERSION: Release 27.
OBSERVATION: The HP Time-Shared BASIC system sets a limit on the time
allowed between dataset connection and login. By default, this is 120
seconds but may be changed by the PHONES system operator command. If the
user does not complete a login within the time allowed, the dataset will be
disconnected.
This action occurs as expected on the 2000E system, but while reconnecting
to the port succeeds, the line is unresponsive. More importantly,
attempting to SLEEP the system hangs after responding to the "MAG TAPE
SLEEP?" question.
CAUSE: Examining the source code where the SLEEP hang occurs shows that
the system is waiting in a loop for output to complete on the disconnected
port. The forced disconnect code, which is shared by the PHONES, KILLID,
and SLEEP commands, calls the BYE processor to log out an active user.
However, for a PHONES disconnect, the user is not logged in. The BYE
processor handles this condition correctly, but it returns to a common
routine (LLEND) that outputs a line feed to the port. The multiplexer
simulation omits a write to a disconnected port but also erroneously omits
the output completion interrupt request. Consequently, TSB believes that
the output is still in progress and therefore waits, in an infinite loop,
for the completion interrupt that never occurs. Also, while the port is in
output mode, input is turned off, so the port appears to be unresponsive
when reconnected.
RESOLUTION: Modify "muxo_svc" (hp2100_mux.c) to set "mux_xdon" to 1 to
trigger the completion interrupt regardless of whether or not the port is
connected to a Telnet session.
STATUS: Fixed in Release 28.
======================
Release 27, 2017-09-06
======================
This release of the HP 2100 simulator adds the following features:
- Support for the HP 2613, 2617, and 2618 line printers has been added to the
LPT device. The default printer remains the HP 2607.
- The LPT device simulation has been rewritten to support realistic and
optimized timing, compact and expanded output modes, custom VFU tape images,
and tracing of internal operations.
- The LOAD command has been rewritten to load files containing absolute binary
loaders into the protected address space of the 21xx machines and configure
the I/O instructions. For the 1000, LOAD can also be used to load boot
loader ROM images other than those provided directly by the simulator.
- The DUMP command has been added to write the binary loader currently resident
in memory to an absolute binary file.
- The TTY punch unit and the LPS, LPT, and PTP devices now position a newly
attached file at the end of the file rather than at the start. As a result,
output will append to, rather than overwrite, the existing content.
- The DA, DP, DQ, and DS disc devices add the PROTECT and UNPROTECT options.
These replace the now-deprecated LOCKED and WRITEENABLED options and more
accurately reflect the labelling of the data protection switches on the disc
drives.
- The simulator message that is displayed when a programmed halt occurs has
been changed to indicate that the halt code comes from the T-register value.
- The Basic Binary Loader (BBL) is now installed by default in the 21xx
machines. It is automatically configured to the select code of the paper
tape reader. It may be overwritten with a different loader (e.g., the Basic
Binary Disc Loader or Basic Moving-head Disc Loader) using the LOAD command.
Performing a power-on reset of the CPU reinstalls the BBL.
- Symbolic display and entry has been rewritten to improve efficiency and
expanded to cover the full instruction set including optional microcode
extensions that are currently enabled.
- CPU instruction execution and data accesses may be selectively traced. The
resulting trace listing is similar to the output of a logic analyzer
connected to the CPU and I/O buses.
- DMA/DCPC commands, status, and data accesses may be selectively traced.
- TBG commands, status, and service entries may be selectively traced.
- The DIAG option of the TBG device has been replaced with the REALTIME, W1A,
W1B, W2A, and W2B options. Configuring the TBG to run its diagnostic now
uses the REALTIME and W2B options, and restoring the normal configuration
uses the CALTIME and W2A options. The W1A and W1B options extend the
software compatibility of the TBG.
- The MUXM device has been renamed MUXC to reflect that it is the multiplexer
control card. The previous MUXM name is deprecated but will still work in
existing simulation command files.
- The multiplexer control card (MUXC) may be enabled and disabled independently
of the upper and lower data cards (MUX and MUXL), reflecting its optional
status in hardware configurations.
- Memory address parsing for commands has been changed to add <page>.<offset>
format for physical addresses, where both the page and the offset range from
0 to 1777 octal. Linear addressing is now restricted to the 32K logical
address space (0 to 77777 octal). Memory display uses linear addressing for
locations within the logical address space; locations above 32K use the
physical address format.
- The previously separate STOP_INST, STOP_DEV, STOP_IOE, and INDMAX
pseudo-registers used to stop the simulator under certain conditions have
been replaced by the SET CPU STOP=<stopname>[,<stopname>...] and the SET CPU
INDIR=<limit> commands. Stops may be temporarily bypassed by adding the -B
switch to the command that resumes execution.
- The HP 2100 Simulator User's Guide has been rewritten and significantly
expanded.
--------------------
Implementation Notes
--------------------
- The simulator passes the HP 2613/17/18 line printer diagnostic as described
in the "hp2100_diag.txt" file.
- The line printer terminates each print line with the 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 LOAD command can no longer be used to read general absolute binary paper
tape images into memory. The ATTACH PTR and BOOT PTR commands must now be
used to read paper tapes.
- The OS, OSTBG, VMA, EMA, VIS, and SIGNAL CPU debug flags have been removed.
Tracing of these firmware instructions is now performed by specifying SET CPU
DEBUG=EXEC and SET CPU EXEC with the appropriate opcode range and mask, as
follows:
* SET CPU DEBUG=OS => SET CPU EXEC=105340;177760
* SET CPU DEBUG=VMA => SET CPU EXEC=105240;177760
* SET CPU DEBUG=EMA => SET CPU EXEC=105240;177760
* SET CPU DEBUG=VIS => SET CPU EXEC=101460;173760
* SET CPU DEBUG=SIGNAL => SET CPU EXEC=105600;177760
- The separate tracing of time-base generator interrupt instructions provided
by the OS and OSTBG CPU debug flags is no longer supported. Entering the
replacement command above traces all OS instructions, including the TBG
interrupt instructions.
- The TIMER, RRR 16, .FLUN, and the OS/VMA, VIS, and SIGNAL self-test
instructions are no longer exempt from the undefined/unimplemented
instruction stop tests. Attempted execution of these instructions without
the appropriate firmware options installed will cause simulation stops if the
UNDEF (TIMER and RRR) or UNIMPL (.FLUN and self-tests) option is enabled.
Because of this change, the default state of the unimplemented instruction
stop has been reversed from "on" to "off".
- The "stop on I/O error" features controlled by the STOP_IOE register values
have been removed from the DR, LPS, LPT, MSC, MTC, and PTP devices, as all of
these report I/O error status to the CPU via their interface input registers.
STOP_IOE has been removed from the PTR device and replaced with SET CPU
STOP=IOERR, as this device does not report I/O error status to the CPU
through its interface.
- The LOCKED and WRITEENABLED options for the MSC and MTC devices are
deprecated. The supported method of write-protecting a tape drive is to
attach the tape image with the -R (read-only) switch or by setting the host
operating system's read-only attribute on the tape image file. This
simulates removing the write ring from the tape reel before mounting it on
the drive. There is no hardware method of write-protecting a mounted and
positioned tape reel.
- If the previous ATTACH behavior (overwriting rather than appending) is
desired for the TTY punch unit and the LPS, LPT, and PTP devices, set the
device's (P)POS register to 0 after attaching.
----------
Bugs Fixed
----------
1. PROBLEM: EXAMINE -M for addresses > 32K displays misleading operands.
VERSION: Release 26.
OBSERVATION: Current-page memory references of instructions residing above
the 32K logical address space are printed as though they reside at their
locations modulo 32K. For example, DEPOSIT 170001 026020 and EXAMINE -M
170001 displays JMP 70020, and DEPOSIT 200001 026020 displays JMP 20.
CAUSE: The printed addresses assume that the instructions will be executed
from their respective pages (modulo 32). However, instructions can be
executed only when they are mapped into the logical address space, and any
given physical page may be mapped to any arbitrary logical page.
Therefore, the address printed may not represent the actual logical address
after mapping.
RESOLUTION: Modify "fprint_cpu" (hp2100_sys.c) to use Z/C address notation
for memory references in instructions residing in physical memory above
32K.
STATUS: Fixed in Release 27.
2. PROBLEM: Enabling IOP firmware should not be allowed on the 1000 F-Series.
VERSION: Release 26.
OBSERVATION: The command "SET CPU 1000-F,IOP" is allowed, but it should
not be, as the IOP firmware is not supported on this machine.
CAUSE: The F-Series does not provide the firmware mapping table entries
that permit operation of the 2000/Access I/O Processor firmware. IOP
instruction opcodes 10x400-17 and 10x420-37 are marked as "HP Reserved" in
the F-Series mapping table, and opcodes 10x460-77 are dedicated to the VIS
microcode.
RESOLUTION: Modify the "cpu_features" array (hp2100_cpu.c) to remove the
IOP option from the 1000 F-Series entry.
STATUS: Fixed in Release 27.
3. PROBLEM: A rejected model change still changes the CPU options.
VERSION: Release 26.
OBSERVATION: Changing to a CPU model that does not support the current
memory size will reduce memory to the maximum supported by the new model.
If the truncated portion contains non-zero values, the simulator will ask
for confirmation before proceeding. If the truncation is rejected, the CPU
options are still set to those of the new model, even though the old model
is retained. For example:
sim> SET CPU 1000-F,128K
sim> SHOW CPU
CPU idle disabled
128KW, 1000-F, EAU
FP, no IOP, DMS
FFP, DBI, no EMA/VMA
no VIS, no SIGNAL
sim> DEPOSIT 100000 1
sim> SET CPU 2116
Really truncate memory [N]?NO
Command not completed
sim> SHOW CPU
CPU idle disabled
128KW, 1000-F, no EAU
no FP, no IOP, no DMS
no FFP, no DBI, no EMA/VMA
no VIS, no SIGNAL
CAUSE: The CPU options are set before the memory size is changed, so when
the size change is rejected, the new CPU options are retained.
RESOLUTION: Modify "cpu_set_model" (hp2100_cpu.c) to perform the memory
size change first, so that if it is rejected, the CPU options have not been
changed.
STATUS: Fixed in Release 27.
4. PROBLEM: Virtual memory mapping fails for accesses above 126 MB.
VERSION: Release 26.
OBSERVATION: A program using virtual memory provided by the RTE-6/VM
operating system may access up to 128 MB of data, although VMA programs
default to a 16 MB limit. Accesses to data in virtual memory are mapped
through the last two DMS user map registers. Normally, each VMA access
maps in the memory page corresponding to the virtual address plus the
following memory page. This allows access to single items up to 1024 words
in size starting at any offset within the (first) page.
If a data item resides in the last 2 MB of virtual memory, access to an
item that crosses the page boundary is incorrect. Instead of accessing
words in the second page, the accesses wrap around within the first page.
CAUSE: The suit number part of the virtual address is not restored before
checking the allocation status of the page table entry corresponding to the
second (spillover) page. As a result, an unallocated second page in the
last 2 MB of virtual memory is seen as beyond the VM area limit, and
instead of generating a page fault to allocate the second page, the map
registers are set up to prevent access to the second page by setting the
first page address into both map registers.
RESOLUTION: Modify "cpu_vma_lbp" (hp2100_cpu5.c) to check for spill page
allocation correctly.
STATUS: Fixed in Release 27.
5. PROBLEM: Memory expansion is not disabled when DMS is disabled.
VERSION: Release 26.
OBSERVATION: If the Memory Expansion Module in a 1000-Series CPU has been
enabled, and then the DMS firmware option is disabled or the CPU is changed
to a model that does not support memory expansion (e.g., a 2100), memory
expansion remains enabled. In this case, memory accesses should revert to
physical addressing, but instead logical-to-physical address translation
through the currently enabled map remains in effect.
CAUSE: Disabling DMS should set the "dms_enb" flag to 0, but it does not.
RESOLUTION: Modify "set_model" and "set_option" (hp2100_cpu.c) to clear
the "dms_enb" flag if DMS is not enabled after the model or option change.
STATUS: Fixed in Release 27.
======================
Release 26, 2017-05-01
======================
This release of the HP 2100 simulator does not add any new features.
--------------------
Implementation Notes
--------------------
- Starting with the next release, the LOAD command will be rewritten to load
files containing absolute binary loaders into the protected address space of
the 21xx machines and configure the I/O instructions. The LOAD command is
not designed for general loading of absolute binary files, as it does not
initialize the A and B registers as some HP software expects. It is intended
only to install bootstrap loaders. The BOOT PTR command is the proper
simulation of the hardware absolute paper tape loader.
----------
Bugs Fixed
----------
1. PROBLEM: The RWCS debug option shown in the user's guide does not exist.
VERSION: Release 25.
OBSERVATION: The "HP2100 Simulator User's Guide" says that the RWCS debug
option may be specified for the DS and DA devices to trace "disk read/
write/control/status commands." However, entering a SET DS DEBUG=RWCS
command gives an "Invalid argument" error.
CAUSE: The option name is misspelled; the correct option is RWSC.
RESOLUTION: Modify "hp2100_doc.doc" to list the correct option name.
STATUS: Fixed in Release 26.
2. PROBLEM: Halt opcodes 1060xx and 1070xx do not display in mnemonic form.
VERSION: Release 25.
OBSERVATION: Halt instructions 106000-106077 and 107000-107077 are not
displayed in mnemonic form, either directly with an EXAMINE -M command
or in the message displayed for a programmed halt. These instruction
ranges are displayed in octal only.
CAUSE: Section 3.20, "Input/Output Instructions," of the "HP 1000
M/E/F-Series Computers Technical Reference Handbook" (HP 5955-0282, March
1980) says, in part, "Bit 11, where relevant, specifies the A- or
B-register or distinguishes between set control and clear control;
otherwise, bit 11 may be a logic 0 or a logic 1 without affecting the
instruction (although the assembler will assign zeros in this case)." The
HLT instruction does not specify the A/B register, so the valid opcodes are
102000-102077, 103000-103777, 106000-106077, and 107000-107077. However,
the latter two ranges are omitted from the "opcode" and "opc_val" tables
used for decoding.
RESOLUTION: Add the 1060xx/107xx range to the "opc_val" table and a second
"HLT" string to the "opcode" table (hp2100_sys.c) to permit mnemonic
display of this instruction range.
STATUS: Fixed in Release 26.
3. PROBLEM: The SFB (scan for byte) opcode displays as SBT (store byte).
VERSION: Release 25.
OBSERVATION: Entering the "EVAL -M 105767" command should display the
"SFB" mnemonic. Instead, it displays "SBT".
CAUSE: The entry in the opcode mnemonic table corresponding to the 105767
value is "SBT", which is incorrect. It should be "SFB" (SBT is 105764).
RESOLUTION: Modify the "opcode" table (hp2100_sys.c) to use the correct
mnemonic for the SFB instruction.
STATUS: Fixed in Release 26.
4. PROBLEM: Host file system seek errors are not caught.
VERSION: Release 25.
OBSERVATION: The MAC/ICD disc library checks for host file system read or
write errors and returns Uncorrectable Data Error status if an error is
indicated. However, host file system seeks are simply assumed to succeed;
no indication of an error is given if a call fails. A failed seek should
be detected, and a Drive Fault (positioner error) should be returned.
CAUSE: Oversight.
RESOLUTION: Modify "position_sector" (hp2100_disclib.c) to test the
"sim_fseek" call for error status and to simulate a Drive Fault (AGC error)
if the call fails.
STATUS: Fixed in Release 26.
5. PROBLEM: Set Flow Control and Cancel commands fail if port key is not set.
VERSION: Release 25.
OBSERVATION: HP 8-channel multiplexer commands that refer to ports do so
indirectly by passing a port key, rather than a port number. The
key-to-port translation is established by the "Set Port Key" command, which
must be executed before any port-specific commands. If a port key has not
been established, then all port-specific commands should be ignored.
However, the "Cancel first receive buffer" and "Set flow control" commands
cause program corruption if the key has not been set.
CAUSE: The test for key validity is improperly applied for these commands.
RESOLUTION: Modify "exec_command" (hp2100_mpx.c) to ignore these commands
if the port key has not been set.
STATUS: Fixed in Release 26.
6. ENHANCEMENT: Improve the EAU shift and rotate instruction simulations.
VERSION: Release 25.
OBSERVATION: The shift and rotate instructions (ASL, ASR, LSL, LSR, RRL,
and RRR) perform 32-bit operations on the combined B and A registers. The
original implementation treated the 16-bit registers independently.
However, it is faster and smaller to form a 32-bit operand, apply the
operation, and then split the operand back into the B and A registers.
Modern compilers, such as gcc, recognize the shifting and masking patterns
necessary for a rotation and generate a single rotate-left or rotate-right
machine instruction.
RESOLUTION: Modify "cpu_eau" (hp2100_cpu1.c) to reimplement the shift and
rotate instructions as 32-bit operations.
STATUS: Fixed in Release 26.
======================
Release 25, 2017-01-11
======================
This is the initial checkpoint release of the HP 2100 simulator, corresponding
to the 25th set of changes to the simulator code base. The following devices
are currently simulated:
- 2114C CPU with up to 16 KW of memory
- 2115A CPU with up to 8 KW of memory
- 2116C CPU with up to 32 KW of memory
- 2100A CPU with up to 32 KW of memory
- 1000 M/E/F-Series CPU with up to 1024 KW of memory
- EAU, FP, IOP, DMS, FFP, DBI, VIS, and SIGNAL microcode extensions
- RTE-IV EMA or RTE-6/VM OS and VMA microcode extensions
- 12531C Buffered Teleprinter Interface with one 2752 Teleprinter
- 12539C Time Base Generator
- 12557A Disc Controller with four 2870 drives
- 12559C Magnetic Tape Controller with one 3030 drive
- 12565A Disc Controller with two 2883 drives
- 12566B Microcircuit Interface with a loopback connector
- 12578A Direct Memory Access Controller
- 12581A Memory Protect
- 12597A Duplex Register Interface with one 2748 Paper Tape Reader
- 12597A Duplex Register Interface with one 2895 Paper Tape Punch
- 12606B Fixed Head Disc Controller with one 2770/2771 drive
- 12607B Direct Memory Access Controller
- 12610B Drum Controller with one 2773/2774/2775 drive
- 12620A Privileged Interrupt Fence
- 12653A Printer Controller with one 2767 Line Printer
- 12792C 8-Channel Asynchronous Multiplexer
- 12821A Disc Interface with four 7906H/7920H/7925H drives
- 12845B Printer Controller with one 2607 Line Printer
- 12875A Interprocessor Link
- 12892B Memory Protect
- 12895A Direct Memory Access Controller
- 12897B Dual-Channel Port Controller
- 12920A 16-Channel Terminal Multiplexer
- 12936A Privileged Interrupt Fence
- 12966A Buffered Asynchronous Communications Interface
- 13037D Disc Controller with eight 7905/7906/7920/7925 drives
- 13181A Magnetic Tape Controller with four 7970B drives
- 13183A Magnetic Tape Controller with four 7970E drives
- 13210A Disc Controller with four 7900 drives
The "HP 2100 Simulator User's Guide" manual describes the configuration and
operation of each of these devices in detail.
--------------------
Implementation Notes
--------------------
- New bug fixes will now be listed in this file under the associated release
rather than in their previous location (hp2100_bugfixes.txt).
- Starting with the next release, the LOAD command will restrict its operation
to the addresses occupied by the bootstrap loaders, i.e., the last 64
locations in memory (up to 32K). The LOAD command is not designed for
general loading of absolute binary files, as it does not initialize the A and
B registers as some HP software expects. It is intended only to install
bootstrap loaders. The BOOT PTR command is the proper simulation of the
hardware absolute paper tape loader.
----------
Bugs Fixed
----------
1. PROBLEM: DPC device documentation uses the wrong disc drive model number.
VERSION: Release 24.
OBSERVATION: The comments in the hp2100_dpc.c source file and Section 2 of
the "HP2100 Simulator User's Guide" say that the DPC device supports the
2871 disc drive, while Section 2.6.1 of the User's Guide says that the
support is for the 2781 disc drive. Neither of these model numbers is
correct.
Contemporaneous literature (e.g., the "2116B Computer Price List," dated
June 1970) states that the disc memory subsystem consists of the HP 2870A
Moving Head Disc, HP 2871A Disc Controller, HP 2881A Power Supply, and HP
2882A Cabinet.
CAUSE: The controller model number is used instead of the drive model
number, while the "2781" number is a transposition of "2871."
RESOLUTION: Modify the initial comments in the DPC device source file
(hp2100_dpc.c) and modify the sections of the HP2100 Simulator User's Guide
to use the correct disc drive model number (2870).
STATUS: Fixed in Release 25.
2. PROBLEM: The BOOT DRC command does not execute correctly.
VERSION: Release 24.
OBSERVATION: Attempting to boot DOS from a fixed-head disc or drum does
not work. The CPU sits in a loop waiting for DMA to finish, but it never
does.
CAUSE: The DMA control word in the DR device bootstrap is not configured
during BOOT DRC processing, so DMA is communicating with the wrong device.
RESOLUTION: Modify "drc_boot" (hp2100_dr.c) to set the fixed disc/drum
select code into the DMA control word before returning.
STATUS: Fixed in Release 25.
3. PROBLEM: The valid command "DEPOSIT 2000 JMP 2001" is rejected.
VERSION: Release 24.
OBSERVATION: Regarding symbolic input, the HP2100 User's Manual says that
the "C" and "Z" flags, signifying a current-page or zero-page reference,
respectively, are not needed "...when entering [memory reference]
instructions into CPU memory; the simulator figures out from the target
address what mode to use." While the valid command "DEPOSIT 1000 JMP 1001"
correctly enters a zero-page jump into memory, the valid command "DEPOSIT
2000 JMP 2001" does not enter a current-page jump. Instead, an "Invalid
argument" error occurs.
CAUSE: The "parse_sym" routine looks for the optional "C" or "Z" flag when
parsing memory reference instructions and sets a flag if either is
specified. The test for a current-page reference is performed only if the
reference type was not explicitly specified. However, the sense of the
test is reversed.
RESOLUTION: Modify "parse_sym" (hp2100_sys.c) to correct the test for C/Z
option specification.
STATUS: Fixed in Release 25.
4. PROBLEM: The invalid command "DEPOSIT 2000 JMP C 2001" is accepted.
VERSION: Release 24.
OBSERVATION: Regarding symbolic input, the HP2100 User's Manual says that
"The address is an octal number in the range 0 - 77777; if C or Z is
specified, the address is a page offset in the range 0 - 1777." However,
specifying a page offset > 1777 is accepted without complaint if it is
within the current page range.
CAUSE: Error checking for memory reference instruction entry is
incomplete.
RESOLUTION: Modify "parse_sym" (hp2100_sys.c) to ensure that the range
check is enforced if either C or Z is specified.
STATUS: Fixed in Release 25.
5. PROBLEM: Punched output does not appear on TTY devices lacking a paper
tape punch.
VERSION: Release 24.
OBSERVATION: Running the HP contributed library program "HP 2000F BASIC
for DOS-M/DOS III" does not produce any console output when using terminal
driver DVR00 as required by the program. When using alternate terminal
driver DVR05, console output appears but console input does not work
properly.
CAUSE: DOS-M and DOS-III support two modes of console I/O: ASCII mode and
binary mode. ASCII mode appends carriage-return/line-feed characters on
output and strips them on input. Binary mode sends and receives bytes
exactly as supplied.
DVR00 is required because DVR05 does not support the binary I/O mode
required by the program. However, DVR00 assumes that a binary write is to
be directed to the console's paper tape punch rather than the console
printer and therefore sets the TTY interface's "punch flip-flop" instead of
the "print flip-flop" to accompany the text output. The simulation of the
HP 12531 interface card associated with the TTY device discards output if
the punch flip-flop is set and the punch unit (TTY2) is not attached.
The problem occurs because only a connected HP 2754 teleprinter (a modified
Teletype ASR35) reacts to the print and punch flip-flop signals. All other
supported terminal devices ignore the signals and print whatever output is
supplied (an HP 2752 -- a rebadged ASR33 -- has a manual control for the
punch, but the punch and printer operate together when the punch is on).
The 2000F BASIC program apparently was designed for use with one of these
other terminals, which print normally even though only the punch flip-flop
is set.
RESOLUTION: Modify "tto_out" (hp2100_stddev.c) to honor the print and
punch flip-flop settings and separate the output as directed only if the
console punch unit is attached (simulating an HP 2754). When the unit is
detached, all output is delivered to the console printer, regardless of the
flip-flop settings (simulating all other console devices).
STATUS: Fixed in Release 25.
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