To:	Users
From:	Bob Supnik
Subj:	HP2100 Simulator Usage
Date:	22-Dec-2004

			COPYRIGHT NOTICE

The following copyright notice applies to both the SIMH source and binary:

   Original code published in 1993-2004, written by Robert M Supnik
   Copyright (c) 1993-2004, Robert M Supnik

   Permission is hereby granted, free of charge, to any person obtaining a
   copy of this software and associated documentation files (the "Software"),
   to deal in the Software without restriction, including without limitation
   the rights to use, copy, modify, merge, publish, distribute, sublicense,
   and/or sell copies of the Software, and to permit persons to whom the
   Software is furnished to do so, subject to the following conditions:

   The above copyright notice and this permission notice shall be included in
   all copies or substantial portions of the Software.

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   ROBERT M SUPNIK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
   IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

   Except as contained in this notice, the name of Robert M Supnik shall not
   be used in advertising or otherwise to promote the sale, use or other dealings
   in this Software without prior written authorization from Robert M Supnik.

This memorandum documents the HP 2100 simulator.


1. Simulator Files

sim/		scp.h
		sim_console.h
		sim_defs.h
		sim_fio.h
		sim_rev.h
		sim_sock.h
		sim_tape.h
		sim_timer.h
		sim_tmxr.h
		scp.c
		sim_console.c
		sim_fio.c
		sim_sock.c
		sim_tape.c
		sim_timer.c
		sim_tmxr.c

sim/hp2100/	hp2100_defs.h
		hp2100_cpu.c
		hp2100_fp.c
		hp2100_dp.c
		hp2100_dq.c
		hp2100_dr.c
		hp2100_ds.c
		hp2100_ipl.c
		hp2100_lps.c
		hp2100_lpt.c
		hp2100_mt.c
		hp2100_ms.c
		hp2100_mux.c
		hp2100_stddev.c
		hp2100_sys.c

2. HP2100 Features

The HP2100 simulator is configured as follows:

device		simulates
name(s)

CPU		2116 CPU with 32KW memory
		2100 CPU with 32KW memory, FP or IOP instructions
		21MX-M/E CPU with 1024KW memory, FP, DMS, and/or IOP instructions
MP		12892B memory protect
DMA0, DMA1	12895A/12897B direct memory access/dual channel port controller
PTR		12597A duplex register interface with 2748 paper tape reader
PTP		12597A duplex register interface with 2895 paper tape punch
TTY		12531C buffered teleprinter interface with 2752 teleprinter
LPS		12653A printer controller with 2767 line printer
		12566B microcircuit interface with loopback connector
LPT		12845B printer controller with 2607 line printer
CLK		12539C time base generator
MUX,MUXL,MUXM	12920A terminal multiplexor
DP		12557A disk controller with four 2871 drives
		13210A disk controller with four 7900 drives
DQ		12565A disk controller with two 2883 drives
DR		12606B fixed head disk controller with 2770/2771 disk
		12610B drum controller with 2773/2774/2775 drum
DS		13037 disk controller with eight 7905/7906/7920/7925 drives
MT		12559C magnetic tape controller with one 3030 drive
MS		13181A magnetic tape controller with four 7970B drives
		13183A magnetic tape controller with four 7970E drives
IPLI		12566B interprocessor link, input side
IPLO		12566B interprocessor link, output side

The HP2100 simulator implements several unique stop conditions:

	- decode of an undefined instruction, and STOP_INST is set
	- reference to an undefined I/O device, and STOP_DEV is set
	- more than INDMAX indirect references are detected during
	  memory reference address decoding

The HP2100 loader supports standard absolute binary format.  The DUMP
command is not implemented.

2.1 CPU

CPU options include choice of instruction set and memory size.  The
general command form is:

	SET {-F} CPU <option>

Options that may be specified are:

	SET CPU 2116		2116 CPU
	SET CPU 2100		2100 CPU
	SET CPU 21MX-M		21MX M-series CPU
	SET CPU 21MX-E		21MX E-series CPU
	SET CPU EAU		EAU instructions (2116 only)
	SET CPU NOEAU		no EAU instructions (2116 only)
	SET CPU FP		FP instructions (2100 only)
	SET CPU NOFP		no FP instructions (2100 only)
	SET CPU IOP		IOP instructions (2100, 21MX only)
	SET CPU NOIOP		no IOP instructions (2100, 21MX only)
	SET CPU DMS		DMS instructions (21MX only)
	SET CPU NODMS		no DMS instructions (21MX only)
	SET CPU 4K		set memory size = 4K
	SET CPU 8K		set memory size = 8K
	SET CPU 16K		set memory size = 16K
	SET CPU 32K		set memory size = 32K
	SET CPU 64K		set memory size = 64K (21MX only)
	SET CPU 128K		set memory size = 128K (21MX only)
	SET CPU 256K		set memory size = 256K (21MX only)
	SET CPU 512K		set memory size = 512K (21MX only)
	SET CPU 1024K		set memory size = 1024K (21MX only)

On the 2100, EAU is standard, and the FP and IOP options are mutually
exclusive.  On the 21MX, EAU and FP are standard.  The 21MX optionally
includes DMS (dynamic mapping system) and IOP instructions.  The 21MX-E
supports the TIMER instruction; on the 21MX-M, this instruction decodes
as MPY.

Setting the CPU type to 2116, 2100, or 21MX establishes a consistent set
of common options.  Additional SET CPU commands may follow to fine-tune
the desired feature set.

The initial memory size is 32K.  Memory sizes larger than 32K are
supported only on the 21MX.  If the memory size is being reduced, either
by setting a smaller size or by changing the CPU model from 21MX to 2116
or 2100 when the current memory size is more than 32K, and the memory
being truncated contains non-zero data, the simulator asks for
confirmation before proceeding.  The confirmation request may be
suppressed by using the "-F" switch.  Data in the truncated portion of
memory is lost.

These switches are recognized when examining or depositing in CPU memory:

	-v			if DMS enabled, interpret address as virtual
	-s			if DMS enabled, force system map
	-u			if DMS enabled, force user map
	-p			if DMS enabled, force port A map
	-q			if DMS enabled, force port B map

The CPU implements four different kinds of instruction breakpoints:

	-e			break unconditionally
	-n			break if DMS is disabled
	-s			break if DMS enabled and system map
	-u			break if DMS enabled and user map

CPU registers include the visible state of the processor as well as the
control registers for the interrupt system.

	name		models		size	comments

	P		all		15	program counter
	A		all		16	A register
	B		all		16	B register
	M		all		15	M (memory address) register
	T		all		16	T (memory data) register
	X		21MX		16	X index register
	Y		21MX		16	Y index register
	S		all		16	switch/display register
	E		all		1	extend flag
	O		all		1	overflow flag
	ION		all		1	interrupt enable flag
	ION_DEFER	all		1	interrupt defer flag
	CIR		all		6	central interrupt register
	DMSENB		21MX		1	DMS enable
	DMSCUR		21MX		1	DMS current map (1 = user map)
	DMSSR		21MX		16	DMS status register
	DMSVR		21MX		16	DMS violation register
	DMSMAP[128]	21MX		16	DMS maps
						[0:31] system map
						[32:63] user map
						[64:95] port A map
						[96:127] port B map
	STOP_INST	all		1	stop on undefined instruction
	STOP_DEV	all		1	stop on undefined device
	INDMAX		all		16	indirect address limit
	PCQ[0:63]	all		15	P of last JMP, JSB, or interrupt;
						most recent P change first

BOOT CPU implements the 21MX IBL facility.  IBL is controlled by the switch
register S.  S<15:14> selects the device to boot:

	00		2748B paper-tape reader (12992K ROM)
	01		7900A/2883 disk (12992A ROM)
	10		7970B/E tape (12992D ROM)
	11		undefined

For the 7900A/2883 only, S<13:12> specify the type of disk:

	00		7900A
	10		2883

S<11:6> contains the device address.  If the device has two addresses, S<11:6>
specifies the lower address.  S<5:3> are passed to the bootstrap program.
S<2:0> specify options for the boot loader.  IBL will not report an error if
the device address in S<11:6> is incorrect.

2.2 Memory Protect

Memory protect is standard equipment on the 2100 (although it may be
disabled by removing a jumper) and optional on the 2116 and 21MX.  The
following registers are implemented:

	name		size	comments

	CTL		1	memory protection enable
	FLG		1	protection violation flag
	FBF		1	protection violation flag buffer
	FR		15	fence register
	VR		16	violation register
	EVR		1	enable violation register flag
	MEV		1	memory expansion (DMS) violation flag

The 21MX memory protect card (12892B) has three feature options that
are implemented by jumper settings.  These are controlled by the
following commands:

	SET MP JSBIN		jumper W5 installed
	SET MP JSBOUT		jumper W5 removed
	SET MP INTIN		jumper W6 installed
	SET MP INTOUT		jumper W6 removed
	SET MP SEL1IN		jumper W7 installed
	SET MP SEL1OUT		jumper W7 removed

W5 determines whether JSB instructions referencing memory locations 0
and 1 are legal (installed) or illegal (removed).  W6 controls whether
the first three levels of indirect addressing hold off (installed) or
permit (removed) pending interrupts.  W7 determines whether I/O
instructions referencing select codes other than 1 are legal (installed)
or illegal (removed); note that I/O instructions referencing select code
1 are legal, and HLT instructions are illegal, regardless of the setting
of W7.

The default configuration is JSB (W5) installed, INT (W6) installed, and
SEL1 (W7) removed, providing compatibility with the 2116 and 2100 memory
protect cards.

2.3 DMA/DCPC Controllers

The direct memory access/dual channel port controller is an option for
all three CPUs.  DMA/DCPC provides two channel controllers (DMA0 and
DMA1).  Each DMA channel has the following visible state:

	name		size	comments

	CMD		1	channel enabled
	CTL		1	interrupt enabled
	FLG		1	channel ready
	FBF		1	channel ready buffer
	CTLALT		1	command word 2/3 selector
	CW1		16	command word 1
	CW2		16	command word 2
	CW3		16	command word 3

2.4 Variable Device Assignments

On the HP2100, I/O device take their device numbers from the backplane
slot they are plugged into.  Thus, device number assignments vary
considerably from system to system, and software package to software
package.  The HP2100 simulator supports dynamic device number assignment.
To show the current device number, use the SHOW <dev> DEVNO command:

	sim> SHOW PTR DEV
	device=10

To change the device number, use the SET <dev> DEVNO=<num> command:

	sim> SET PTR DEV=30
	sim> SHOW PTR DEV
	device=30

The new device number must be in the range 010..077 (octal).  For devices
with two device numbers, only the lower numbered device number can be
changed; the higher is automatically set to the lower + 1.  If a
device number conflict occurs, the simulator will return an error
when started.

2.4.1 Device State

All devices other than the CPU and TTY may be disabled or enabled.
Disabling a device simulates removing the associated interface from the
CPU card cage.  To disable or enable a device, use:

	SET <dev> DISABLED	disable device
	SET <dev> ENABLED	enable device

For devices with more than one device number, disabling or enabling any
device in the set disables or enables all of the devices.

Devices consisting of multiple addressible units connected to a controller
typically allow the units to be individually enabled or disabled.  Disabled
simulates disconnecting the associated unit from the controller.  The
commands to set units enabled and disabled are:

	SET <unit> DISABLED	disable unit
	SET <unit> ENABLED 	enable unit

Some devices and units allow simulation of power-down conditions.  Power
settings are controlled by these commands:

	SET <dev> POWEROFF	turn power off
	SET <dev> POWERON	turn power on

Peripherals that provide operator-selectable disconnection, typically via an
"offline" switch, provide these simulation equivalents:

	SET <dev> OFFLINE	set peripheral offline
	SET <dev> ONLINE	set peripheral online

2.5 Programmed I/O Devices

2.5.1 12597A-002 Duplex Register Interface (PTR) with 2748 Paper Tape Reader

The paper tape reader (PTR) reads data from a disk file.  For diagnostic
purposes, a tape loop may be simulated with the commands:

	SET PTR DIAG		rewind tape at EOF
	SET PTR READER		supply tape trailer at EOF

The paper tape reader supports the BOOT command.  BOOT PTR copies the
IBL into memory and starts it running.  The switch register (S) is
set automatically to the value expected by the IBL loader:

	<15:12>	=	0000
	<11:6>	=	device code
	<5:3> = 	unchanged
	<2:0> =		000

The paper tape reader implements these registers:

	name		size	comments

	BUF		8	last data item processed
	CMD		1	reader enable
	CTL		1	device/interrupt enable
	FLG		1	device ready
	FBF		1	device ready buffer
	SRQ		1	device DMA service request
	TRLLIM		8	number of trailing nulls to append
				after end-of-file is detected
	POS		32	position in the input file
	TIME		24	time from I/O initiation to interrupt
	STOP_IOE	1	stop on I/O error

The TRLLIM register specifies the number of nulls to supply as paper
tape trailer when EOF is detected.  If TRLLIM is set to zero or the
count is exhausted, the reader will hang.

The POS register specifies the number of the next data item to be read.
Thus, by changing POS, the user can backspace or advance the reader.

Error handling is as follows:

	error	     STOP_IOE	processed as

	not attached	1	report error and stop
			0	out of tape

	end of file	1	report error and stop
			0	out of tape

	OS I/O error	x	report error and stop

2.5.2 12597A-005 Duplex Register Interface (PTP) with 2895 Paper Tape Punch

The paper tape punch (PTP) writes data to a disk file.  The POS
register specifies the number of the next data item to be written.
Thus, by changing POS, the user can backspace or advance the punch.

The paper tape punch implements these registers:

	name		size	comments

	BUF		8	last data item processed
	CMD		1	punch enable
	CTL		1	device/interrupt enable
	FLG		1	device ready
	FBF		1	device ready buffer
	SRQ		1	device DMA service request
	POS		32	position in the output file
	TIME		24	time from I/O initiation to interrupt
	STOP_IOE	1	stop on I/O error

Error handling is as follows:

	error	     STOP_IOE	processed as

	not attached	1	report error and stop
			0	out of tape

	OS I/O error	x	report error and stop

2.5.3 12531C Buffered Teleprinter Interface (TTY) with 2752 Teleprinter

The console teleprinter has three units: keyboard (unit 0), printer
(unit 1), and punch (unit 2).  The keyboard reads from the console
keyboard; the printer writes to the simulator console window.  The punch
writes to a disk file.  The keyboard and printer units (TTY0, TTY1) can
be set to one of three modes: UC, 7B, or 8B.  In UC mode, lower case
input and output characters are automatically converted to upper case.
In 7B mode, input and output characters are masked to 7 bits.  In 8B
mode, characters are not modified.  In UC and 7B mode, output of control
characters other than BEL, BS, HT, LF, and CR is suppressed; in 8B mode,
output of all characters is permitted.  Changing the mode of either the
keyboard or the printer changes both.  The default mode is UC.

Some HP software systems expect the console to transmit line-feed
automatically following carriage-return.  This feature is enabled with:

	SET TTY AUTOLF

and disabled with:

	SET TTY NOAUTOLF

The console teleprinter implements these registers:

	name		size	comments

	BUF		8	last data item processed
	MODE		16	mode
	CTL		1	device/interrupt enable
	FLG		1	device ready
	FBF		1	device ready buffer
	SRQ		1	device DMA service request
	KPOS		32	number of characters input
	KTIME		24	keyboard polling interval
	TPOS		32	number of characters printed
	TTIME		24	time from I/O initiation to interrupt
	PPOS		32	position in the punch output file
	STOP_IOE	1	punch stop on I/O error

Error handling for the punch is as follows:

	error	     STOP_IOE	processed as

	not attached	1	report error and stop
			0	out of tape

	OS I/O error	x	report error and stop

2.5.4 12653A Printer Controller (LPS) with 2767 Line Printer
      12566B Microcircuit Interface with Loopback Connector

The 2767 line printer uses the 12653A line printer interface as
its controller.  As a line printer, LPS writes data to a disk file.
The POS register specifies the number of the next data item to be
written.  Thus, by changing POS, the user can backspace or advance
the printer.

The line printer responds to SET LPS POWEROFF as if the power were removed
or the printer cable were disconnected and DETACH LPS as if the paper were
out.  It also provides these additional state commands:

	SET LPS OFFLINE		simulate ONLINE button up
	SET LPS ONLINE		simulate ONLINE button down
	SET LPS REALTIME	use realistic timing for print operations
	SET LPS FASTTIME	use optimized timing for print operations

As a 12566B microcircuit interface, LPS provides the test device for
running several of the HP diagnostics.  Printer mode verus diagnostic
mode is controlled by the commands:

	SET LPS PRINTER		configure as line printer
	SET LPS DIAG		configure for diagnostic tests

In diagnostic mode, LPS simulates the installation of the HP 1251-0332
diagnostic test (loopback) connector onto the 12566B card.

LPS may be configured to send debugging information to the previously
enabled debug output device using these commands:

	SET LPS DEBUG		provide debug printouts
	SET LPS NODEBUG		inhibit debug printouts

Diagnostic information includes characters supplied to and status received
from the interface, as well as data transfer initiations and completions.

The 12653A is disabled by default.

The 12653A implements these registers:

	name		size	comments

	BUF		16	output buffer
	STA		16	input buffer or status
	POWER		2	printer power state
	CMD		1	printer enable
	CTL		1	device/interrupt enable
	FLG		1	device ready
	FBF		1	device ready buffer
	SRQ		1	device DMA service request
	CCNT		7	current character count
	LCNT		7	current line count
	POS		32	position in the output file
	CTIME		24	character transfer time
	PTIME		24	per-zone print operation time
	STIME		24	per-line paper slew time
	RTIME		24	power-on ready delay time
	STOP_IOE	1	stop on I/O error

In printer mode, error handling is as follows:

	error	     STOP_IOE	processed as

	not attached	1	report error and stop
			0	out of paper

	SET POWEROFF	1	report error and stop
			0	powered off

	SET OFFLINE	1	report error and stop
			0	offline

	OS I/O error	x	report error and stop

With STOP_IOE set to 0, output performed when the device is powered off
or offline will initiate but then hang, waiting for the device to be
returned online.  When it is, the output operation will complete.

In diagnostic mode, there are no errors; data sent to the output
buffer is looped back to the status register with a fixed delay of 1.

2.5.5 12845B Printer Controller (LPT) with 2607 Line Printer

The line printer (LPT) writes data to a disk file.  The POS register
specifies the number of the next data item to be written.  Thus,
by changing POS, the user can backspace or advance the printer.

The line printer responds to SET LPT POWEROFF as if the power were
removed or the printer cable were disconnected and DETACH LPT as if the
paper were out.  It also provides these additional state commands:

	SET LPT OFFLINE		simulate PAPER button up
	SET LPT ONLINE		simulate PAPER button down

The line printer implements these registers:

	name		size	comments

	BUF		8	last data item processed
	CMD		1	printer enable
	CTL		1	device/interrupt enable
	FLG		1	device ready
	FBF		1	device ready buffer
	SRQ		1	device DMA service request
	LCNT		7	line count within page
	POS		32	position in the output file
	CTIME		24	time between characters
	PTIME		24	time for a print operation
	STOP_IOE	1	stop on I/O error

Error handling is as follows:

	error	     STOP_IOE	processed as

	not attached	1	report error and stop
			0	out of paper

	SET POWEROFF	1	report error and stop
			0	powered off

	SET OFFLINE	1	report error and stop
			0	offline

	OS I/O error	x	report error and stop

With STOP_IOE set to 0, output performed when the device is powered off
or offline will initiate but then hang, waiting for the device to be
returned online.  When it is, the output operation will complete.

2.5.6 12539C Time Base Generator (CLK)

The time base generator (CLK) may be set for diagnostic mode:

	SET CLK DIAG		configure for diagnostic mode
	SET CLK CALIBRATED	configure for timing mode

Diagnostic mode corresponds to setting jumper W2 to position "B".  This
turns off autocalibration and divides the longest time intervals down by
1000.

The time base generator implements these registers:

	name		size	comments

	SEL		3	time base select
	CTR		14	repeat counter for < 1Hz operation
	CTL		1	device/interrupt enable
	FLG		1	device ready
	FBF		1	device ready buffer
	ERR		1	error flag
	TIME[0:7]	31	clock intervals, select = 0..7
	DEVNO		6	current device number (read only)

The time base generator autocalibrates; the clock interval is adjusted
up or down so that the clock tracks actual elapsed time.  Operation at
the fastest rates (100 usec, 1 msec) is not recommended.

2.5.7 12920A Terminal Multiplexor (MUX, MUXL, MUXM)

The 12920A is a 16-line terminal multiplexor, with five additional
receive-only diagnostic lines.  It consists of three devices:

	MUX		scanning logic (corresponding more or less
			to the upper data card)
	MUXL		individual lines (corresponding more or
			less to the lower data card)
	MUXM		modem control and status logic (corresponding
			to the control card)

The MUX performs input and output through Telnet sessions connected to a
user-specified port.  The ATTACH command to the scanning logic specifies
the port to be used:

	ATTACH MUX <port>	set up listening port

where port is a decimal number between 1 and 65535 that is not being used
for other TCP/IP activities.

Each line (each unit of MUXL) can be set to one of three modes: UC, 7B,
or 8B.  In UC mode, lower case input and output characters are converted
automatically to upper case.  In 7B mode, input and output characters
are masked to 7 bits.  In 8B mode, characters are not modified.  The
default mode is UC.  In addition, each line supports the DATASET option.
DATASET, when set, enables modem control.  The default settings are UC
mode and DATASET disabled.  Finally, each line supports output logging.
The SET MUXLn LOG command enables logging on a line:

	SET MUXLn LOG=filename	log output of line n to filename

The SET MUXLn NOLOG command disables logging and closes the open log
file, if any.

The modem controls model a simplified Bell 103A dataset with just four
lines: data terminal ready and request to send from the computer to the
data set, and carrier detect and data set ready from the data set to
the computer.  There is no ring detection.  If data terminal ready is
set when a Telnet connection starts up, then carrier detect and data
set ready are also set.  The connection is established whether data
terminal ready is set or not.

Once MUX is attached and the simulator is running, the multiplexor listens
for connections on the specified port.  It assumes that the incoming
connections are Telnet connections.  The connections remain open until
disconnected either by the Telnet client, a SET MUXL DISCONNECT command,
or a DETACH MUX command.

The SHOW MUX CONNECTIONS command displays the current connections to the
extra terminals.  The SHOW MUX STATISTICS command displays statistics for
active connections.  The SET MUX DISCONNECT=linenumber disconnects the
specified line.

The scanner (MUX) implements these registers:

	name		size	comments

	IBUF		16	input buffer, holds line status
	OBUF		16	output buffer, holds channel select

The lines (MUXL) implements these registers:

	name		size	comments

	CTL		1	device/interrupt enable
	FLG		1	device ready
	FBF		1	device ready buffer
	SRQ		1	device DMA service request
	STA[0:20]	16	line status, lines 0-20
	RPAR[0:20]	16	receive parameters, lines 0-20
	XPAR[0:15]	16	transmit parameters, lines 0-15
	RBUF[0:20]	8	receive buffer, lines 0-20
	XBUF[0:15]	8	transmit buffer, lines 0-15
	RCHP[0:20]	1	receive character present, lines 0-20
	XDON[0:15]	1	transmit done, lines 0-15
	TIME[0:15]	24	transmit time, lines 0-15

The modem control (MUXM) implements these registers:

	name		size	comments

	CTL		1	device/interrupt enable
	FLG		1	device ready
	FBF		1	device ready buffer
	SRQ		1	device DMA service request
	SCAN		1	scan enabled
	CHAN		4	current line
	DSO[0:15]	6	C2,C1,ES2,ES1,SS2,SS1, lines 0-15
	DSI[0:15]	2	S2,S1, lines 0-15


The terminal multiplexor does not support save and restore.  All open
connections are lost when the simulator shuts down or MUX is detached.

2.5.8 Interprocessor Link (IPLI, IPLO)

The interprocessor link is a pair of 12566B parallel interfaces that
are cross coupled to provide interprocessor communications to a second
copy of the HP2100 simulator.  The IPL is intended to support simulation
of a two system HP TimeShared Basic configuration.  The links are actually
bidirectional half-duplex; TimeShared Basic uses them unidirectionally.
The IPL is disabled by default.

To operate, the IPL devices must be enabled and then connected to the IPL
devices in another copy of the simulator.  The IPLI device in the first
simulator is connected to the IPLO device in the second, and vice versa.
Connections are established with the ATTACH command.  One copy of the
simulator listens for connections on a specified port (ATTACH -L); the
other establishes connections to an IP address and port (ATTACH -C).
Either copy may perform either operation, but the operations must be
done in matched pairs:

	simulator #1			simulator #2

	sim> set ipli ena		sim> set ipli ena
	(also enables iplo)		(also enables iplo)
	sim> att -lw ipli 4000
	Listening on port 4000
	Waiting for connection
					sim> att -c iplo 4000
	Connection established		Connected to 127.0.0.1 port 4000
	sim> att -lw iplo 4000
	Listening on port 4001
	Waiting for connection
					sim> att -c ipli 4001
	Connection established		Connected to 127.0.0.1 port 4000

Both forms of ATTACH take a modifier -W (wait); if specified, the command
will wait up to 30 seconds for the connection process to complete.  ATTACH
-C can specify both an IP address and a port, in the form aa.bb.cc.dd:port;
if the IP address is omitted, it defaults to 127.0.0.1 (local system).

Both IPLI and IPLO implement the BOOT command.  BOOT loads the HP Access
Basic Block Loader for the IOP into the top 64 words of memory and starts
it running.

Both IPLI and IPLO implement these registers:

	name		size	comments

	BUF		16	buffer
	HOLD		8	holding buffer
	CMD		1	device enable
	CTL		1	device/interrupt enable
	FLG		1	device ready
	FBF		1	device ready buffer
	SRQ		1	device DMA service request
	TIME		24	polling interval for input
	STOP_IOE	1	stop on I/O error

2.6 Disk Controllers

2.6.1 12557A Disk Controller (DPC, DPD) with Four 2781 Drives
      13210A Disk Controller (DPC, DPD) with Four 7900 Drives

The 12557A/13210A disk controller can be configured as either a
12557A, supporting 2.5MB drives, or a 13210A, supporting 5MB drives,
with the commands:

	SET DPC 12557A		2.5MB drives
	SET DPC 13210A		5.0MB drives

Drive types cannot be intermixed; the controller is configured for
one type or the other.  The 13210A (for 7900/7901 disks) is selected
by default.

The simulated controller has two separate devices, a data channel and
a command channel.  The data channel includes a 128-word (one sector)
buffer for reads and writes.  The command channel includes the four
disk drives.  Disk drives can be set DISABLED or ENABLED.

Individual drives may be protected against writing.  These commands
simulate the Upper/Lower Disc Protect switches on the drives:

	SET DPCn LOCKED		set unit n write locked
	SET DPCn WRITEENABLED	set unit n write enabled

Separate protection for the upper and lower platters of the 7900 drive
is not supported.  Also, the drive Protect/Override switch is not
supported; drive protection is permanently overridden.

The 12557A/13210A supports the BOOT command.  BOOT DPC copies the IBL
for 7900 class disks into memory and starts it running.  BOOT -R DPC
boots from the removable platter (head 0).  The switch register (S) is
set automatically to the value expected by the IBL loader:

	<15:14>	=	01
	<13:12>	=	00
	<11:6>	=	data channel device code
	<5:3> = 	unchanged
	<2:1> =		00
	<0> =		1 if booting from the removable platter

The data channel implements these registers:

	name		size	comments

	IBUF		16	input buffer
	OBUF		16	output buffer
	DBUF[0:127]	16	sector buffer
	BPTR		7	sector buffer pointer
	CMD		1	channel enable
	CTL		1	interrupt enable
	FLG		1	channel ready
	FBF		1	channel ready buffer
	SRQ		1	channel DMA service request
	XFER		1	transfer in progress flag
	WVAL		1	write data valid flag

The command channel implements these registers:

	name		size	comments

	OBUF		16	output buffer
	BUSY		4	busy (unit #, + 1, of active unit)
	CNT		5	check record count
	CMD		1	controller enable
	CTL		1	interrupt enable
	FLG		1	controller ready
	FBF		1	controller ready buffer
	SRQ		1	controller DMA service request
	EOC		1	end of cylinder pending
	POLL		1	attention polling enabled
	RARC		8	record address register (cylinder)
	RARH		2	record address register (head)
	RARS		4	record address register (sector)
	CYL[0:3]	8	current cylinder, drives 0-3
	STA[0:3]	16	drive status, drives 0-3
	CTIME		24	data transfer command delay time
	DTIME		24	data channel command delay time
	STIME		24	seek delay time, per cylinder
	XTIME		24	interword transfer time

Error handling is as follows:

	error	     		processed as

	not attached		disk not ready (drive unloaded)

	end of file		assume rest of disk is zero

	OS I/O error		report error and stop

2.6.2 12565A Disk Controller (DQC, DQD) with Two 2883 Drives

The 12565A disk controller has two separate devices, a data channel and
a command channel.  The data channel includes a 128-word (one sector)
buffer for reads and writes.  The command channel includes the two
disk drives.  Disk drives can be set DISABLED or ENABLED.

Individual drives may be protected against writing:

	SET DQCn LOCKED		set unit n write locked
	SET DQCn WRITEENABLED	set unit n write enabled

The 12565A supports the BOOT command.  BOOT DQC copies the IBL for 2883
class disks into memory and starts it running.  The switch register (S)
is set automatically to the value expected by the IBL loader:

	<15:12>	=	0110
	<11:6>	=	data channel device code
	<5:3> = 	unchanged
	<2:0> =		000

The data channel implements these registers:

	name		size	comments

	IBUF		16	input buffer
	OBUF		16	output buffer
	DBUF[0:127]	16	sector buffer
	BPTR		7	sector buffer pointer
	CMD		1	channel enable
	CTL		1	interrupt enable
	FLG		1	channel ready
	FBF		1	channel ready buffer
	SRQ		1	channel DMA service request
	XFER		1	transfer in progress flag
	WVAL		1	write data valid flag

The command channel implements these registers:

	name		size	comments

	OBUF		16	output buffer
	BUSY		2	busy (unit # + 1 of active unit)
	CNT		9	check record count
	CMD		1	controller enable
	CTL		1	interrupt enable
	FLG		1	controller ready
	FBF		1	controller ready buffer
	SRQ		1	controller DMA service request
	RARC		8	record address register (cylinder)
	RARH		5	record address register (head)
	RARS		5	record address register (sector)
	CYL[0:1]	8	current cylinder, drives 0-1
	HED[0:1]	5	current head, drives 0-1
	STA[0:1]	16	drive status, drives 0-1
	CTIME		24	data transfer command delay time
	DTIME		24	data channel command delay time
	STIME		24	seek delay time, per cylinder
	XTIME		24	interword transfer time

Error handling is as follows:

	error	     		processed as

	not attached		disk not ready

	end of file		assume rest of disk is zero

	OS I/O error		report error and stop

2.6.3 12606B Fixed Head Disk Controller (DRC, DRD) with 2770/2771 Disk
      12610B Drum Controller (DRC, DRD) with 2773/2774/2775 Drum

The 12606B/12610B fixed head disk/drum controller has two separate devices,
a data channel and a command channel.

The command channel includes the actual drive.  Ten different models are
supported:

	command		interface and size	model

	SET DRC 180K	12606B, 180K words	2770A
	SET DRC 360K	12606B, 360K words	2771A
	SET DRC 720K	12606B, 720K words	2771A-001
	SET DRC 384K	12610B, 384K words	2773A
	SET DRC 512K	12610B, 512K words	2773A-001
	SET DRC 640K	12610B, 640K words	2773A-002
	SET DRC 768K	12610B, 768K words	2774A
	SET DRC 896K	12610B, 896K words	2774A-001
	SET DRC 1024K	12610B, 1024K words	2774A-002
	SET DRC 1536K	12610B, 1536K words	2775A

The command channel supports write-protected tracks.  Track protection
is enabled with this command:

	SET DRC PROTECTED

In addition, the number of protected tracks is specified by the command:

	SET DRC TRACKPROT=count

The track protect count must be a power of two from 1 to 128 on the 12606
interface and from 1 to 512, or 768, on the 12610 interface.  If the drive
has fewer tracks than the track protect count, then all tracks on the drive
are eligible for protection.

Track protection is disabled with this command:

	SET DRC UNPROTECTED

The 12606B/12610B support the BOOT command.  The BOOT command loads the
first sector from the disk or drum into locations 0-77 and then jumps to 77.
This is very different from the IBL loader protocol used by the 12565A and
the 12557A/13210A.

The data channel implements these registers:

	name		size	comments

	IBUF		16	input buffer
	OBUF		16	output buffer
	CMD		1	channel enable
	CTL		1	interrupt enable
	FLG		1	channel ready
	FBF		1	channel ready buffer
	SRQ		1	channel DMA service request
	BPTR		6	sector buffer pointer

The command channel implements these registers:

	name		size	comments

	CW		16	command word
	STA		16	status
	RUN		1	run flip-flop
	CMD		1	controller enable
	CTL		1	interrupt enable
	FLG		1	controller ready
	FBF		1	controller ready buffer
	SRQ		1	controller DMA service request
	TIME		24	interword transfer time
	STOP_IOE	1	stop on I/O error

Error handling is as follows:

	error	     	processed as

	not attached	disk not ready

12606B/12610B data files are buffered in memory; therefore, end of file
and OS I/O errors cannot occur.

2.6.4 13037 Disk Controller (DS) with Eight 7905/7906/7920/7925 Drives

The 13037 disk controller supports 7905 (15MB), 7906 (20MB), 7920 (50MB),
or 7925 (120MB) disk drives, as well as autosizing, based on the size
of the disk image file:

	SET DSn 7905		drive n is a 15MB drive
	SET DSn 7906		drive n is a 20MB drive
	SET DSn 7920		drive n is a 50MB drive
	SET DSn 7925		drive n is a 120MB drive
	SET DSn AUTOSIZE	drive n type based on file size at attach

Drive types can be intermixed.  The 7905 is selected by default.  Drives
can be set DISABLED or ENABLED.

Individual drives may be protected against writing.  These commands
simulate the Disc Protect/Read Only switches on the drives:

	SET DSn LOCKED		set unit n write locked
	SET DSn WRITEENABLED	set unit n write enabled

Separate protection for the upper and lower platters of the 7905 and
7906 drives is not supported.  Protecting a 7905 or 7906 drive behaves
as though both of the Disc Protect switches were on.

The setting of the drive Format switch may be changed with:

	SET DSn FORMAT		set format enabled
	SET DSn NOFORMAT	set format disabled

The 13037 supports the BOOT command.  BOOT DS copies the IBL loader for
the 13037 controller into memory and starts it running.  The switch register
(S) is set automatically to the value expected by the IBL loader:

	<15:14>	=	11
	<13:12>	=	01
	<11:6>	=	data channel device code
	<5:3> = 	unchanged
	<2> =		0
	<1:0> =		unchanged (head number)

The DS controller implements these registers:

	name		size	comments

	CMD		16	command register
	FIFO[0:15]	16	data FIFO
	SR1		16	status register 1
	VCTR		16	verify counter
	FMASK		8	file mask
	CYL		16	cylinder address register
	HS		16	head/sector address register
	STATE		2	controller state
	LASTA		3	last unit polled for attention flag
	FIP		4	FIFO insertion pointer
	FRP		4	FIFO removal pointer
	FCNT		5	FIFO counter
	CTL		1	interrupt enable
	FLG		1	ready flag
	FBF		1	ready flag buffer
	SRQ		1	DMA service request
	BUSY		1	visible busy status
	CMDF		1	command follows flag
	CMDP		1	command pending flag
	EOC		1	end of cylinder flag
	EOD		1	end of data flag
	DBUF[0:127]	16	sector buffer
	DPTR		8	sector buffer pointer
	CTIME		24	command response time
	DTIME		24	data transfer response time
	STIME		24	seek time (per cylinder)
	RTIME		24	rotation time
	TIMEOUT		31	controller timeout

Error handling is as follows:

	error	     		processed as

	not attached		disk not ready

	end of file		assume rest of disk is zero

	OS I/O error		report error and stop

2.7 Magnetic Tape

2.7.1 12559C Magnetic Tape Controller (MTC, MTD) with One 3030 Drive

Magnetic tape options include the ability to make the unit write enabled
or write locked.

	SET MTC LOCKED		set unit write locked
	SET MTC WRITEENABLED	set unit write enabled

The 12559C mag tape drive has two separate devices, a data channel and
a command channel.  The data channel includes a maximum record sized
buffer for reads and writes.  The command channel includes the tape
unit.

The BOOT command is not supported.  The 12559C was HP's earliest tape
drive and is not supported by most of its operating systems.  It is
disabled by default.

The data channel implements these registers:

	name		size	comments

	FLG		1	channel ready
	SRQ		1	channel DMA service request
	DBUF[0:65535]	8	transfer buffer
	BPTR		16	buffer pointer (reads and writes)
	BMAX		16	buffer size (writes)

The command channel implements these registers:

	name		size	comments

	FNC		8	current function
	STA		9	tape status
	BUF		8	buffer
	CTL		1	interrupt enabled
	FLG		1	controller ready
	FBF		1	controller ready buffer
	SRQ		1	controller DMA service request
	DTF		1	data transfer flop
	FSVC		1	first service flop
	POS		32	magtape position
	CTIME		24	command delay time
	XTIME		24	interword transfer delay time
	STOP_IOE	1	stop on I/O error

Error handling is as follows:

	error			processed as

	not attached		tape not ready; if STOP_IOE, stop

	end of file		parity error

	OS I/O error		parity error; if STOP_IOE, stop

2.7.2 13181A Magnetic Tape Controller (MSC, MSD) with Four 7970B Drives
      18183A Magnetic Tape Controller (MSC, MSD) with Four 7970E Drives

Magnetic tape options include the ability to make the unit write enabled
or write locked, and the ability to select the 13181A (800 bpi) controller
or the 13183A (1600 bpi) controller.

	SET MSCn LOCKED		set unit n write locked
	SET MSCn WRITEENABLED	set unit n write enabled
	SET MSC 13181A		set controller to 13181A
	SET MSC 13183A		set controller to 13183A
	SET MSC REALTIME	set controller to actual timing
	SET MSC FASTTIME	set controller to optimized timing (default)
	SET MSCn REEL=length	set unit tape reel size
				0 = unlimited (default)
				600 = 600 feet
				1200 = 1200 feet
				2400 = 2400 feet

MSC may be configured to send debugging information to the previously
enabled debug output device using these commands:

	SET MSC DEBUG		provide debug printouts
	SET MSC NODEBUG		inhibit debug printouts

Diagnostic information includes commands supplied to and status received
from the interface, as well as command initiations and completions.

The 13181A/13183A mag tape drive has two separate devices, a data channel
and a command channel.  The data channel includes a maximum record
sized buffer for reads and writes.  The command channel includes the
tape units.

The 13181A/13183A supports the BOOT command.  BOOT MSC loads the IBL for
7970B/E magnetic tape drives into memory and starts it running.  BOOT -S
MSC causes the loader to position to the file number specified in the A
register before starting to load data.  The switch register (S) is set
automatically to the value expected by the IBL loader:

	<15:12>	=	1000
	<11:6>	=	data channel device code
	<5:3> = 	unchanged
	<2:0> =		00
	<0> =		1 if position tape before loading

The data channel implements these registers:

	name		size	comments

	BUF		16	data buffer
	CTL		1	interrupt enabled
	FLG		1	channel ready
	FBF		1	channel ready buffer
	SRQ		1	channel DMA service request
	DBUF[0:65535]	8	transfer buffer
	BPTR		17	buffer pointer (reads and writes)
	BMAX		17	buffer size (writes)

The command channel implements these registers:

	name		size	comments

	STA		12	tape status
	BUF		16	buffer
	USEL		2	currently selected unit
	FSVC		1	first service flop
	CTL		1	interrupt enabled
	FLG		1	controller ready
	FBF		1	controller ready buffer
	SRQ		1	controller DMA service request
	POS[0:3]	32	magtape position
	BTIME		24	BOT start delay time
	CTIME		24	command delay time
	GTIME		24	gap traversal time
	ITIME		24	IRG traversal time
	RTIME		24	rewind initiation time
	XTIME		24	interword transfer delay time
	STOP_IOE	1	stop on I/O error

Error handling is as follows:

	error			processed as

	not attached		tape not ready; if STOP_IOE, stop

	end of file		parity error

	OS I/O error		parity error; if STOP_IOE, stop

2.8 Symbolic Display and Input

The HP2100 simulator implements symbolic display and input.  Display is
controlled by command line switches:

	-a			display as ASCII character
	-c			display as two character string
	-m			display instruction mnemonics

Input parsing is controlled by the first character typed in or by command
line switches:

	' or -a			ASCII character
	" or -c			two character sixbit string
	alphabetic		instruction mnemonic
	numeric			octal number

Instruction input uses standard HP2100 assembler syntax.  There are seven
instruction classes: memory reference, I/O, shift, alter skip, extended
shift, extended memory reference, extended two address reference.

Memory reference instructions have the format

	memref {C/Z} address{,I}

where I signifies indirect, C a current page reference, and Z a zero page
reference.  The address is an octal number in the range 0 - 077777; if C or
Z is specified, the address is a page offset in the range 0 - 01777.  Normally,
C is not needed; the simulator figures out from the address what mode to use.
However, when referencing memory outside the CPU (eg, disks), there is no
valid PC, and C must be used to specify current page addressing.

IOT instructions have the format

	io device{,C}

where C signifies that the device flag is to be cleared.  The device is an
octal number in the range 0 - 77.

Shift and alter/skip instructions have the format

	sub-op sub-op sub-op...

The simulator checks that the combination of sub-opcodes is legal.

Extended shift instructions have the format

	extshift count

where count is an octal number in the range 1 - 020.

Extended memory reference instructions have the format

	extmemref address{,I}

where I signifies indirect addressing.  The address is an octal number in
the range 0 - 077777.

Extended two address instructions have the format

	ext2addr addr1{,I},addr2{,I}

where I signifies indirect addressing.  Both address 1 and address 2 are
octal numbers in the range 0 - 077777.
