098200a126
1. New Features in 3.3-2 1.1 SCP and Libraries - Added ASSERT command (from Dave Bryan) 1.2 PDP-11, VAX - Added RA60, RA71, RA81 disks 2. Bugs Fixed in 3.3-2 2.1 H316 - Fixed IORETURN macro - PT: fixed bug in OCP '0001 (found by Philipp Hachtmann) - MT: fixed error reporting from OCP (found by Philipp Hachtmann) 2.2 Interdata 32b - Fixed branches to mask new PC (from Greg Johnson) 2.3 PDP-11 - Fixed bugs in RESET for 11/70 (reported by Tim Chapman) - Fixed bug in SHOW MODEL (from Sergey Okhapkin) - Made SYSID variable for 11/70 (from Tim Chapman) - Fixed MBRK write case for 11/70 (from Tim Chapman) - RY: fixed bug in boot code (reported by Graham Toal) 2.4 VAX - Fixed initial state of cpu_extmem 2.5 HP2100 (from Dave Bryan) - Fixed missing MPCK on JRS target - Removed EXECUTE instruction (is NOP in actual microcode) - Fixed missing negative overflow renorm in StoreFP 2.6 I1401 - Fixed bug in line printer write line (reported by Van Snyder)
863 lines
26 KiB
Text
863 lines
26 KiB
Text
To: Users
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From: Bob Supnik
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Subj: PDP-8 Simulator Usage
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Date: 15-Feb-2005
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COPYRIGHT NOTICE
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The following copyright notice applies to both the SIMH source and binary:
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Original code published in 1993-2005, written by Robert M Supnik
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Copyright (c) 1993-2005, Robert M Supnik
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Permission is hereby granted, free of charge, to any person obtaining a
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copy of this software and associated documentation files (the "Software"),
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to deal in the Software without restriction, including without limitation
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the rights to use, copy, modify, merge, publish, distribute, sublicense,
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and/or sell copies of the Software, and to permit persons to whom the
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Software is furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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ROBERT M SUPNIK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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Except as contained in this notice, the name of Robert M Supnik shall not
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be used in advertising or otherwise to promote the sale, use or other dealings
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in this Software without prior written authorization from Robert M Supnik.
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This memorandum documents the PDP-8 simulator.
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1. Simulator Files
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sim/ scp.h
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sim_console.h
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sim_defs.h
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sim_fio.h
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sim_rev.h
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sim_sock.h
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sim_tape.h
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sim_timer.h
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sim_tmxr.h
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scp.c
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sim_console.c
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sim_fio.c
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sim_sock.c
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sim_tape.c
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sim_timer.c
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sim_tmxr.c
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sim/pdp8/ pdp8_defs.h
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pdp8_cpu.c
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pdp8_df.c
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pdp8_dt.c
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pdp8_lp.c
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pdp8_mt.c
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pdp8_pt.c
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pdp8_rf.c
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pdp8_rk.c
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pdp8_rl.c
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pdp8_rx.c
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pdp8_sys.c
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pdp8_td.c
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pdp8_tsc.c
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pdp8_tt.c
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pdp8_ttx.c
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2. PDP-8 Features
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The PDP-8 simulator is configured as follows:
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device simulates
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name(s)
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CPU PDP-8/E CPU with 4KW-32KW of memory
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- KE8E extended arithmetic element (EAE)
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- KM8E memory management and timeshare control
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TSC TSC8-75 ETOS operating system timeshare control
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PTR,PTP PC8E paper tape reader/punch
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TTI,TTO KL8E console terminal
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TTIX,TTOX KL8JA additional terminals
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LPT LE8E line printer
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CLK DK8E line frequency clock (also PDP-8/A compatible)
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RK RK8E/RK05 cartridge disk controller with four drives
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RF RF08/RS08 fixed head disk controller with 1-4 platters, or
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DF DF32/DS32 fixed head disk controller with 1-4 platters
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RL RL8A/RL01 cartridge disk controller with four drives
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RX RX8E/RX01, RX28/RX02 floppy disk controller with two drives
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DT TC08/TU56 DECtape controller with eight drives
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TD TD8E/TU56 DECtape controller with two drives
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MT TM8E/TU10 magnetic tape controller with eight drives
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Most devices can be disabled or enabled, by the commands:
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SET <dev> DISABLED
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SET <dev> ENABLED
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The simulator allows most device numbers to be changed, by the command:
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SET <dev> DEV=<number>
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The PDP-8 can support only one of the set {DF32, RF08, RL8A} using the
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default device numbers, since they all use device numbers 60-61. The
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default is the RF08. To change the disk at device numbers 60-61:
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sim> SET RF DISABLED disable RF08
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sim> SET DF ENABLED, or enable DF32
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sim> SET RL ENABLED enable RL8A
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The PDP-8 can only support one of the set {TC08, TD8E} using the default
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device numbers, since both use device number 77. The default is the
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TC08. To change the DECtape controller to the TD8E:
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sim> SET DT DISABLED disable TC08
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sim> SET TD ENABLED enable TD8E
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Alternately, the device conflict can be eliminated by changing device
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numbers:
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sim> SET RL DEV=50
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sim> SET RL ENA
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sim> SET TD DEV=74
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sim> SET TD ENA
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However, devices can only be BOOTed with their default device numbers.
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The PDP-8 simulator implements several unique stop conditions:
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- if an undefined instruction (unimplemented IOT or OPR) is
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decoded, and register STOP_INST
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- if a simulated DECtape runs off the end of its reel
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The PDP-8 loader supports both RIM format and BIN format tapes. If the file
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extension is .RIM, or the -r switch is specified with LOAD, the file is
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assumed to be RIM format; if the file extension is not .RIM, or if the -b
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switch is specified, the file is assumed to be BIN format.
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2.1 CPU
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The only CPU options are the presence of the EAE and the size of main
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memory; the memory extension and time-share control is always included,
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even if memory size is 4K.
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SET CPU EAE enable EAE
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SET CPU NOEAE disable EAE
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SET CPU 4K set memory size = 4K
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SET CPU 8K set memory size = 8K
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SET CPU 12K set memory size = 12K
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SET CPU 16K set memory size = 16K
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SET CPU 20K set memory size = 20K
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SET CPU 24K set memory size = 24K
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SET CPU 28K set memory size = 28K
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SET CPU 32K set memory size = 32K
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If memory size is being reduced, and the memory being truncated contains
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non-zero data, the simulator asks for confirmation. Data in the truncated
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portion of memory is lost. Initial memory size is 32K.
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CPU registers include the visible state of the processor as well as the
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control registers for the interrupt system.
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name size comments
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PC 15 program counter, including IF as high 3 bits
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AC 12 accumulator
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MQ 12 multiplier-quotient
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L 1 link
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SR 12 front panel switches
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IF 3 instruction field
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DF 3 data field
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IB 3 instruction field buffer
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SF 7 save field
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UF 1 user mode flag
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UB 1 user mode buffer
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SC 5 EAE shift counter
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GTF 1 EAE greater than flag
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EMODE 1 EAE mode (0 = A, 1 = B)
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ION 1 interrupt enable
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ION_DELAY 1 interrupt enable delay for ION
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CIF_DELAY 1 interrupt enable delay for CIF
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PWR_INT 1 power fail interrupt
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UF_INT 1 user mode violation interrupt
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INT 15 interrupt pending flags
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DONE 15 device done flags
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ENABLE 15 device interrupt enable flags
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PCQ[0:63] 15 PC prior to last JMP, JMS, or interrupt;
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most recent PC change first
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STOP_INST 1 stop on undefined instruction
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WRU 8 interrupt character
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The CPU can maintain a history of the most recently executed instructions.
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This is controlled by the SET CPU HISTORY and SHOW CPU HISTORY commands:
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SET CPU HISTORY clear history buffer
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SET CPU HISTORY=0 disable history
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SET CPU HISTORY=n enable history, length = n
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SHOW CPU HISTORY print CPU history
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SHOW CPU HISTORY=n print first n entries of CPU history
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The maximum length for the history is 65536 entries.
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2.2 TSC8-75 ETOS Timeshare Control (TSC)
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ETOS is a timeshared operating system for the PDP-8, providing multiple
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virtual OS/8 environments for up to 32 users. It requires a special
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timeshare control option, the TSC8-75. The TSC8-75 is normally disabled;
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to run ETOS, it must be enabled with the command:
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SET TSC ENABLED
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The TSC8-75 implements these registers:
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IR most recently trapped instruction
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PC PC of most recently trapped instruction
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CDF 1 if trapped instruction is CDF, 0 otherwise
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ENB interrupt enable flag
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INT interrupt pending flag
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Except for operation of ETOS, the TSC8-75 should be left disabled.
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2.3 Programmed I/O Devices
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2.3.1 PC8E Paper Tape Reader (PTR)
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The paper tape reader (PTR) reads data from a disk file. The POS
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register specifies the number of the next data item to be read. Thus,
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by changing POS, the user can backspace or advance the reader.
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The paper tape reader supports the BOOT command. BOOT PTR copies the
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RIM loader into memory and starts it running.
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The paper tape reader implements these registers:
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name size comments
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BUF 8 last data item processed
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DONE 1 device done flag
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ENABLE 1 interrupt enable flag
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INT 1 interrupt pending flag
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POS 32 position in the input file
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TIME 24 time from I/O initiation to interrupt
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STOP_IOE 1 stop on I/O error
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Error handling is as follows:
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error STOP_IOE processed as
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not attached 1 report error and stop
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0 out of tape
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end of file 1 report error and stop
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0 out of tape
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OS I/O error x report error and stop
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2.3.2 PC8E Paper Tape Punch (PTP)
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The paper tape punch (PTP) writes data to a disk file. The POS register
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specifies the number of the next data item to bewritten. Thus, by
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changing POS, the user can backspace or advance the punch.
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The paper tape punch implements these registers:
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name size comments
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BUF 8 last data item processed
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DONE 1 device done flag
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ENABLE 1 interrupt enable flag
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INT 1 interrupt pending flag
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POS 32 position in the output file
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TIME 24 time from I/O initiation to interrupt
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STOP_IOE 1 stop on I/O error
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Error handling is as follows:
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error STOP_IOE processed as
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not attached 1 report error and stop
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0 out of tape
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OS I/O error x report error and stop
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2.3.3 KL8E Terminal Input (TTI)
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The terminal interfaces (TTI, TTO) can be set to one of three modes:
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KSR, 7B, or 8B. In KSR mode, lower case input and output characters
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are automatically converted to upper case, and the high order bit is
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forced to one on input. In 7B mode, input and output characters are
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masked to 7 bits. In 8B mode, characters are not modified. Changing
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the mode of either interface changes both. The default mode is KSR.
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The terminal input (TTI) polls the console keyboard for input. It
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implements these registers:
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name size comments
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BUF 8 last data item processed
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DONE 1 device done flag
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ENABLE 1 interrupt enable flag
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INT 1 interrupt pending flag
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POS 32 number of characters input
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TIME 24 keyboard polling interval
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2.3.4 KL8E Terminal Output (TTO)
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The terminal output (TTO) writes to the simulator console window. It
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implements these registers:
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name size comments
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BUF 8 last data item processed
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DONE 1 device done flag
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ENABLE 1 interrupt enable flag
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INT 1 interrupt pending flag
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POS 32 number of characters output
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TIME 24 time from I/O initiation to interrupt
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2.3.5 LE8E Line Printer (LPT)
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The line printer (LPT) writes data to a disk file. The POS register
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specifies the number of the next data item to be read or written. Thus,
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by changing POS, the user can backspace or advance the printer.
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The line printer implements these registers:
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name size comments
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BUF 8 last data item processed
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ERR 1 error status flag
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DONE 1 device done flag
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ENABLE 1 interrupt enable flag
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INT 1 interrupt pending flag
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POS 32 position in the output file
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TIME 24 time from I/O initiation to interrupt
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Error handling is as follows:
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error STOP_IOE processed as
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not attached 1 report error and stop
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0 set error flag
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OS I/O error x report error and stop
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2.3.6 DK8E Line-Frequency Clock (CLK)
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The real-time clock (CLK) frequency can be adjusted as follows:
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SET CLK 60HZ set frequency to 60Hz
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SET CLK 50HZ set frequency to 50Hz
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The default is 60Hz.
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The clock implements these registers:
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name size comments
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DONE 1 device done flag
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ENABLE 1 interrupt enable flag
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INT 1 interrupt pending flag
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TIME 24 clock interval
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The real-time clock autocalibrates; the clock interval is adjusted up or
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down so that the clock tracks actual elapsed time.
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2.3.7 KL8JA Additional Terminals (TTIX, TTOX)
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The additional terminals consist of two independent devices, TTIX and
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TTOX. The entire set is modelled as a terminal multiplexor, with TTIX
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as the master unit. The additional terminals perform input and output
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through Telnet sessions connected to a user-specified port. The ATTACH
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command specifies the port to be used:
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ATTACH TTIX <port> set up listening port
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where port is a decimal number between 1 and 65535 that is not being used
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for other TCP/IP activities.
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The additional terminals can be set to one of three modes: UC, 7B, or
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8B. In UC mode, lower case input and output characters are converted
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automatically to upper case. In 7B mode, input and output characters
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are masked to 7 bits. In 8B mode, characters are not modified. The
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default mode is UC. Finally, each line supports output logging.
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The SET TTOXn LOG command enables logging on a line:
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SET TTOXn LOG=filename log output of line n to filename
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The SET TTOXLn NOLOG command disables logging and closes the open log
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file, if any.
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Once TTIX is attached and the simulator is running, the terminals listen
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for connections on the specified port. They assume that the incoming
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connections are Telnet connections. The connections remain open until
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disconnected either by the Telnet client, a SET TTIX DISCONNECT command,
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or a DETACH TTIX command.
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The SHOW TTIX CONNECTIONS command displays the current connections to the
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extra terminals. The SHOW TTIX STATISTICS command displays statistics for
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active connections. The SET TTIX DISCONNECT=linenumber disconnects the
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specified line.
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The input device (TTIX) implements these registers:
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name size comments
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BUF[0:3] 8 input buffer, lines 0-3
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DONE 4 device done flags (line 0 rightmost)
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ENABLE 4 interrupt enable flag
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INT 4 interrupt pending flag
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TIME 24 initial polling interval
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TPS 10 polls per second after calibration
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The output device (TTOX) implements these registers:
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name size comments
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BUF[0:3] 8 last data item processed, lines 0-3
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DONE 4 device done flag (line 0 rightmost)
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ENABLE 4 interrupt enable flag
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INT 4 interrupt pending flag
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TIME[0:3] 24 time from I/O initiation to interrupt,
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lines 0-3
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The additional terminals do not support save and restore. All open
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connections are lost when the simulator shuts down or TTIX is detached.
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2.3.8 TD8E/TU56 DECtape (TD)
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The TD8E is a programmed I/O, non-interrupt controller, supporting two
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DECtape drives (0 and 1). The TD8E simulator puts a high burden on the
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host processor, because tape activity is simulated a line (3b) at a time.
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Unless the PDP-8 software requires the TD8E, the TC08 should be used
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to simulate DECtapes. The TD8E is disabled by default.
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TD8E options include the ability to make units write enabled or write
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locked.
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SET DTn LOCKED set unit n write locked
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SET DTn WRITEENABLED set unit n write enabled
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Units can also be set ENABLED or DISABLED. The TD8E supports the BOOT
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command, but only for unit 0.
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The TD8E supports supports PDP-8 format, PDP-11 format, and 18b format
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DECtape images. ATTACH tries to determine the tape format from the DECtape
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image; the user can force a particular format with switches:
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-r PDP-8 format
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-s PDP-11 format
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-t 18b format
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The TD8E controller is a data-only simulator; the timing and mark
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track, and block header and trailer, are not stored. Thus, read always
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produces standard values for header and trailer words, and write throws
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header and trailer words into the bit bucket.
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The TD8E controller implements these registers:
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name size comments
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TDCMD 4 command register
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TDDAT 12 data register
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TDMTK 6 mark track register
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TDSLF 1 single line flag
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TDQLF 1 quad line flag
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TDTME 1 timing error flag
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TDQL 2 quad line counter
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LTIME 31 time between lines
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DCTIME 31 time to decelerate to a full stop
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POS[0:7] 32 position, in lines, units 0-7
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STATT[0:7] 18 unit state, units 0-7
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STOP_OFFR 1 stop on off-reel error
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The LTIME parameter should not be changed, or OS/8 may fail to run
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correctly. The DCTIME parameter should always be at least 100 times
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greater than LTIME. Acceleration time is 75% of deceleration time.
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2.4 Moving Head Disks
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2.4.1 RK8E Cartridge Disk (RK)
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RK8E options include the ability to make units write enabled or write locked:
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SET RKn LOCKED set unit n write locked
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SET RKn WRITEENABLED set unit n write enabled
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Units can also be set ENABLED or DISABLED. The RK8E supports the BOOT command.
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The RK8E implements these registers:
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name size comments
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RKSTA 12 status
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RKCMD 12 disk command
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RKDA 12 disk address
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RKMA 12 current memory address
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BUSY 1 control busy flag
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INT 1 interrupt pending flag
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STIME 24 seek time, per cylinder
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RTIME 24 rotational delay
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STOP_IOE 1 stop on I/O error
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Error handling is as follows:
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error STOP_IOE processed as
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not attached 1 report error and stop
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0 disk not ready
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end of file x assume rest of disk is zero
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OS I/O error x report error and stop
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2.4.2 RL8A Cartridge Disk (RL)
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RL8A options include the ability to make units write enabled or write locked:
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SET RLn LOCKED set unit n write locked
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SET RLn WRITEENABLED set unit n write enabled
|
|
|
|
Units can also be set ENABLED or DISABLED. The RL8A supports the BOOT command,
|
|
but only for unit 0.
|
|
|
|
The RL8A implements these registers:
|
|
|
|
name size comments
|
|
|
|
RLCSA 12 control/status A
|
|
RLCSB 12 control/status B
|
|
RLMA 12 memory address
|
|
RLWC 12 word count
|
|
RLSA 6 sector address
|
|
RLER 12 error flags
|
|
RLSI 16 silo top word
|
|
RLSI1 16 silo second word
|
|
RLSI2 16 silo third word
|
|
RLSIL 1 silo read left/right flag
|
|
INT 1 interrupt request
|
|
DONE 1 done flag
|
|
ERR 1 composite error flag
|
|
STIME 1 seek time, per cylinder
|
|
RTIME 1 rotational delay
|
|
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 disk not ready
|
|
|
|
end of file x assume rest of disk is zero
|
|
|
|
OS I/O error x report error and stop
|
|
|
|
2.5 RX8E/RX01, RX28/RX02 Floppy Disk (RX)
|
|
|
|
The RX can be configured as an RX8E with two RX01 drives, or an RX28 with
|
|
two RX02 drives:
|
|
|
|
SET RX RX8E set controller to RX8E/RX01
|
|
SET RX RX28 set controller to RX28/RX02
|
|
|
|
The controller is set to the RX8E by default. The RX28 is not backwards-
|
|
compatible with the RX8E and will not work with the standard OS/8 V3D floppy
|
|
disk driver.
|
|
|
|
RX8E options include the ability to set units write enabled or write locked:
|
|
|
|
SET RXn LOCKED set unit n write locked
|
|
SET RXn WRITEENABLED set unit n write enabled
|
|
|
|
RX28 options include, in addition, the ability to set the unit density to
|
|
single density, double density, or autosized; autosizing is the default:
|
|
|
|
SET RXn SINGLE set unit n single density
|
|
SET RXn DOUBLE set unit n double density
|
|
SET RXn AUTOSIZE set unit n autosize
|
|
|
|
The RX8E and RX28 support the BOOT command.
|
|
|
|
The RX8E and RX28 implement these registers:
|
|
|
|
name size comments
|
|
|
|
RXCS 12 status
|
|
RXDB 12 data buffer
|
|
RXES 12 error status
|
|
RXTA 8 current track
|
|
RXSA 8 current sector
|
|
STAPTR 4 controller state
|
|
BUFPTR 8 buffer pointer
|
|
INT 1 interrupt pending flag
|
|
DONE 1 device done flag
|
|
ENABLE 1 interrupt enable flag
|
|
TR 1 transfer ready flag
|
|
ERR 1 error flag
|
|
CTIME 24 command completion time
|
|
STIME 24 seek time, per track
|
|
XTIME 24 transfer ready delay
|
|
STOP_IOE 1 stop on I/O error
|
|
SBUF[0:255] 8 sector buffer array
|
|
|
|
Error handling is as follows:
|
|
|
|
error STOP_IOE processed as
|
|
|
|
not attached 1 report error and stop
|
|
0 disk not ready
|
|
|
|
RX01 and RX02 data files are buffered in memory; therefore, end of file
|
|
and OS I/O errors cannot occur.
|
|
|
|
2.6 Fixed Head Disks
|
|
|
|
Either the RF08 or the DF32 can be present in a configuration, but
|
|
not both, with default device addressing.
|
|
|
|
2.6.1 RF08/RS08 Fixed Head Disk (RF)
|
|
|
|
RF08 options include the ability to set the number of platters to a
|
|
fixed value between 1 and 4, or to autosize the number of platters
|
|
from the attached file:
|
|
|
|
SET RF 1P one platter (256K)
|
|
SET RF 2P two platters (512K)
|
|
SET RF 3P three platters (768K)
|
|
SET RF 4P four platters (1024K)
|
|
SET RF AUTOSIZE autosized on attach
|
|
|
|
The default is one platter.
|
|
|
|
The RF08 implements these registers:
|
|
|
|
name size comments
|
|
|
|
STA 12 status
|
|
DA 20 current disk address
|
|
MA 12 memory address (in memory)
|
|
WC 12 word count (in memory)
|
|
WLK 32 write lock switches
|
|
INT 1 interrupt pending flag
|
|
DONE 1 device done flag
|
|
TIME 24 rotational delay, per word
|
|
BURST 1 burst flag
|
|
STOP_IOE 1 stop on I/O error
|
|
|
|
The RF08 supports the BOOT command. The default bootstrap is for OS/8. To
|
|
bootstrap the 4K Disk Monitor, use the BOOT -D RF command.
|
|
|
|
The RF08 is a three-cycle data break device. If BURST = 0, word transfers
|
|
are scheduled individually; if BURST = 1, the entire transfer occurs in
|
|
a single data break.
|
|
|
|
Error handling is as follows:
|
|
|
|
error STOP_IOE processed as
|
|
|
|
not attached 1 report error and stop
|
|
0 disk not ready
|
|
|
|
RF08 data files are buffered in memory; therefore, end of file and OS
|
|
I/O errors cannot occur.
|
|
|
|
2.6.2 DF32/DS32 Fixed Head Disk (RF)
|
|
|
|
DF32 options include the ability to set the number of platters to a
|
|
fixed value between 1 and 4, or to autosize the number of platters
|
|
from the attached file:
|
|
|
|
SET DF 1P one platter (32K)
|
|
SET DF 2P two platters (64K)
|
|
SET DF 3P three platters (98K)
|
|
SET DF 4P four platters (128K)
|
|
SET DF AUTOSIZE autosized on attach
|
|
|
|
The default is one platter.
|
|
|
|
The DF32 implements these registers:
|
|
|
|
name size comments
|
|
|
|
STA 12 status, disk and memory address extension
|
|
DA 12 low order disk address
|
|
MA 12 memory address (in memory)
|
|
WC 12 word count (in memory)
|
|
WLK 16 write lock switches
|
|
INT 1 interrupt pending flag
|
|
DONE 1 device done flag
|
|
TIME 24 rotational delay, per word
|
|
BURST 1 burst flag
|
|
STOP_IOE 1 stop on I/O error
|
|
|
|
The DF32 supports the BOOT command. The default bootstrap is for OS/8. To
|
|
bootstrap the 4K Disk Monitor, use the BOOT -D DF command.
|
|
|
|
The DF32 is a three-cycle data break device. If BURST = 0, word transfers
|
|
are scheduled individually; if BURST = 1, the entire transfer occurs in
|
|
a single data break.
|
|
|
|
Error handling is as follows:
|
|
|
|
error STOP_IOE processed as
|
|
|
|
not attached 1 report error and stop
|
|
0 disk not ready
|
|
|
|
DF32 data files are buffered in memory; therefore, end of file and OS
|
|
I/O errors cannot occur.
|
|
|
|
2.7 TC08/TU56 DECtape (DT)
|
|
|
|
DECtapes drives are numbered 1-8; in the simulator, drive 8 is unit 0.
|
|
TC08 options include the ability to make units write enabled or write
|
|
locked.
|
|
|
|
SET DTn LOCKED set unit n write locked
|
|
SET DTn WRITEENABLED set unit n write enabled
|
|
|
|
Units can also be set ENABLED or DISABLED. The TC08 supports the BOOT
|
|
command, but only for unit 0.
|
|
|
|
The TC08 supports supports PDP-8 format, PDP-11 format, and 18b format
|
|
DECtape images. ATTACH tries to determine the tape format from the DECtape
|
|
image; the user can force a particular format with switches:
|
|
|
|
-r PDP-8 format
|
|
-s PDP-11 format
|
|
-t 18b format
|
|
|
|
The TC08 controller is a data-only simulator; the timing and mark
|
|
track, and block header and trailer, are not stored. Thus, the WRITE
|
|
TIMING AND MARK TRACK function is not supported; the READ ALL function
|
|
always returns the hardware standard block header and trailer; and the
|
|
WRITE ALL function dumps non-data words into the bit bucket.
|
|
|
|
The DECtape controller implements these registers:
|
|
|
|
name size comments
|
|
|
|
DTSA 12 status register A
|
|
DTSB 12 status register B
|
|
INT 1 interrupt pending flag
|
|
ENB 1 interrupt enable flag
|
|
DTF 1 DECtape flag
|
|
ERF 1 error flag
|
|
CA 12 current address (memory location 7754)
|
|
WC 12 word count (memory location 7755)
|
|
LTIME 31 time between lines
|
|
DCTIME 31 time to decelerate to a full stop
|
|
SUBSTATE 2 read/write command substate
|
|
POS[0:7] 32 position, in lines, units 0-7
|
|
STATT[0:7] 31 unit state, units 0-7
|
|
STOP_OFFR 1 stop on off-reel error
|
|
|
|
It is critically important to maintain certain timing relationships
|
|
among the DECtape parameters, or the DECtape simulator will fail to
|
|
operate correctly.
|
|
|
|
- LTIME must be at least 6
|
|
- DCTIME needs to be at least 100 times LTIME
|
|
|
|
Acceleration time is set to 75% of deceleration time.
|
|
|
|
2.8 TM8E Magnetic Tape (MT)
|
|
|
|
Magnetic tape options include the ability to make units write enabled or
|
|
or write locked.
|
|
|
|
SET MTn LOCKED set unit n write locked
|
|
SET MTn WRITEENABLED set unit n write enabled
|
|
|
|
Units can also be set ENABLED or DISABLED.
|
|
|
|
The magnetic tape controller implements these registers:
|
|
|
|
name size comments
|
|
|
|
CMD 12 command
|
|
FNC 12 function
|
|
CA 12 memory address
|
|
WC 12 word count
|
|
DB 12 data buffer
|
|
STA 12 main status
|
|
STA2 6 secondary status
|
|
DONE 1 device done flag
|
|
INT 1 interrupt pending flag
|
|
STOP_IOE 1 stop on I/O error
|
|
TIME 24 record delay
|
|
UST[0:7] 24 unit status, units 0-7
|
|
POS[0:7] 32 position, units 0-7
|
|
|
|
Error handling is as follows:
|
|
|
|
error processed as
|
|
|
|
not attached tape not ready; if STOP_IOE, stop
|
|
|
|
end of file bad tape
|
|
|
|
OS I/O error parity error; if STOP_IOE, stop
|
|
|
|
2.9 Symbolic Display and Input
|
|
|
|
The PDP-8 simulator implements symbolic display and input. Display is
|
|
controlled by command line switches:
|
|
|
|
-a display as ASCII character
|
|
-c display as (sixbit) character string
|
|
-t display as (TSS/8 sixbit) 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
|
|
# or -t two character TSS/8 sixbit string
|
|
alphabetic instruction mnemonic
|
|
numeric octal number
|
|
|
|
Instruction input uses standard PDP-8 assembler syntax. There are four
|
|
instruction classes: memory reference, IOT, field change, and operate.
|
|
|
|
Memory reference instructions have the format
|
|
|
|
memref {I} {C/Z} address
|
|
|
|
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 - 07777; if C or
|
|
Z is specified, the address is a page offset in the range 0 - 177. 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 consist of single mnemonics, eg, KRB, TLS. IOT instructions
|
|
may be or'd together
|
|
|
|
iot iot iot...
|
|
|
|
The simulator does not check the legality of the proposed combination. IOT's
|
|
for which there is no opcode may be specified as IOT n, where n is an octal
|
|
number in the range 0 - 0777.
|
|
|
|
Field change instructions (CIF, CDF) have the format
|
|
|
|
fldchg field
|
|
|
|
where field is an octal number in the range 0 - 7. Field change instructions
|
|
may be or'd together.
|
|
|
|
Operate instructions have the format
|
|
|
|
opr opr opr...
|
|
|
|
The simulator does not check the legality of the proposed combination. EAE
|
|
mode A and B mnemonics may be specified regardless of the EAE mode. The
|
|
operands for MUY and DVI must be deposited explicitly.
|