To: Users From: Bob Supnik Subj: SDS 940 Simulator Usage Date: 15-Nov-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 SDS 940 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/sds/ sds_defs.h sds_cpu.c sds_drm.c sds_dsk.c sds_io.c sds_lp.c sds_mt.c sds_mux.c sds_rad.c sds_stddev.c sds_sys.c 2. SDS 940 Features The SDS-940 simulator is configured as follows: device simulates name(s) CPU SDS-940 CPU with 16KW to 64KW of memory CHAN I/O channels PTR paper tape reader PTP paper tape punch TTI console input TTO console output LPT line printer RTC real-time clock MUX terminal multiplexor DRM Project Genie drum RAD fixed head disk DSK 9164/9165 rapid access (moving head) disk MT magnetic tape Most devices can be disabled or enabled with the SET DISABLED and SET ENABLED commands, respectively. 2.1 CPU The CPU options set the size of main memory and the configuration of peripherals. SET CPU 16K set memory size = 16KW SET CPU 32K set memory size = 32KW SET CPU 48K set memory size = 48KW SET CPU 64K set memory size = 64KW SET CPU GENIE enable DRM, set terminal mux to GENIE mode SET CPU SDS disable DRM, set terminal mux to SDS mode If memory size is being reduced, and the memory being truncated contains non-zero data, the simulator asks for confirmation. Data in the truncated portion of memory is lost. Initial memory size is 64KW. CPU registers include the visible state of the processor as well as the control registers for the interrupt system. name size comments P 14 program counter A 24 accumulator A B 24 accumulator B X 24 index register OV 1 overflow indicator EM2 3 memory extension, quadrant 2 EM3 3 memory extension, quadrant 3 RL1 24 user relocation register 1 RL2 24 user relocation register 2 RL4 12 kernel relocation register NML 1 normal mode flag USR 1 user mode flag MONUSR 1 monitor-to-user trap enable ION 1 interrupt enable INTDEF 1 interrupt defer INTREQ 32 interrupt request flags APIACT 5 highest active API level APIREQ 5 highest requesting API level XFRREQ 32 device transfer request flags BPT 4 breakpoint switches ALERT 6 outstanding alert number STOP_INVINS 1 stop on invalid instruction STOP_INVDEV 1 stop on invalid device number STOP_INVIOP 1 stop on invalid I/O operation INDLIM 8 maximum indirect nesting depth EXULIM 8 maximum execute nesting depth PCQ[0:63] 14 P prior to last branch or interrupt; most recent P change first WRU 8 interrupt character The CPU can maintain a history of the most recently executed instructions. This is controlled by the SET CPU HISTORY and SHOW CPU HISTORY commands: SET CPU HISTORY clear history buffer SET CPU HISTORY=0 disable history SET CPU HISTORY=n enable history, length = n SHOW CPU HISTORY print CPU history SHOW CPU HISTORY=n print first n entries of CPU history The maximum length for the history is 65536 entries. 2.2 Channels (CHAN) The SDS 940 has up to eight I/O channels, designated W, Y, C, D, E, F, G, and H. W, Y, C, and D are time-multiplexed communications channels (TMCC); E, F, G, and H are direct access communications channels (DACC). Unlike real SDS 940 channels, the simulated channels handle 6b, 12b, and 24b transfers simultaneously. The association between a device and a channel is displayed by the SHOW CHAN command: SIM> SHOW LPT CHAN channel=W The user can change the association with the SET CHAN= command, where is a channel letter: SIM> SET LPT CHAN=E SIM> SHOW LPT CHAN channel=E Each channel has nine registers. The registers are arrays, with entry [0] for channel W, entry [1] for channel Y, etc. name size comments UAR[0:7] 6 unit address register WCR[0:7] 15 word count register MAR[0:7] 16 memory address register DCR[0:7] 6 data chaining register WAR[0:7] 24 word assembly register CPW[0:7] 2 characters per word CNT[0:7] 3 character count MODE[0:7] 12 channel mode (from EOM instruction) FLAG[0:7] 9 channel flags The user can display all the registers in a channel with the command: SHOW CHAN channel-letter 2.3 Console Input (TTI) The console input (TTI) polls the console keyboard for input. It implements these registers: name size comments BUF 6 data buffer XFR 1 transfer ready flag POS 32 number of characters input TIME 24 polling interval By default, the console input is assigned to channel W. 2.4 Console Output (TTO) The console output (TTO) writes to the simulator console window. It implements these registers: name size comments BUF 6 data buffer XFR 1 transfer ready flag POS 32 number of characters input TIME 24 time from I/O initiation to interrupt By default, the console output is assigned to channel W. 2.5 Paper Tape Reader (PTR) The paper tape reader (PTR) reads data from a disk file. 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. The paper tape reader implements these registers: name size comments BUF 6 data buffer XFR 1 transfer ready flag SOR 1 start of record flag CHAN 4 active channel POS 32 number of characters input 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 end of file 1 report error and stop 0 out of tape OS I/O error x report error and stop By default, the paper tape reader is assigned to channel W. 2.6 Paper Tape Punch (PTP) 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 by changing POS, the user can backspace or advance the punch. The paper tape punch implements these registers: name size comments BUF 6 data buffer XFR 1 transfer ready flag LDR 1 punch leader flag CHAN 4 active channel POS 32 number of characters input 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 By default, the paper tape punch is assigned to channel W. 2.7 Line Printer (LPT) 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 implements these registers: name size comments BUF[0:131] 8 data buffer BPTR 8 buffer pointer XFR 1 transfer ready flag ERR 1 error flag CHAN 4 active channel CCT[0:131] 8 carriage control tape CCTP 8 pointer into carriage control tape CCTL 8 length of carriage control tape SPCINST 24 spacing instruction POS 32 number of characters input CTIME 24 intercharacter time PTIME 24 print time STIME 24 space time 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 OS I/O error x report error and stop By default, the line printer is assigned to channel W. 2.8 Real-Time Clock (RTC) The real-time clock (RTC) frequency can be adjusted as follows: SET RTC 60HZ set frequency to 60Hz SET RTC 50HZ set frequency to 50Hz The default is 60Hz. The clock implements these registers: name size comments PIE 1 interrupt enable TIME 24 tick interval The real-time clock autocalibrates; the clock interval is adjusted up or down so that the clock tracks actual elapsed time. 2.9 Terminal Multiplexor (MUX) The terminal multiplexor provides 32 asynchronous interfaces. In Genie mode, the interfaces are hard-wired; in SDS mode, they implement modem control. The multiplexor has two controllers: MUX for the scanner, and MUXL for the individual lines. The terminal multiplexor performs input and output through Telnet sessions connected to a user-specified port. The ATTACH command specifies the port to be used: ATTACH MUX 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) supports one option: UC, when set, causes lower case input characters to be automatically converted to upper case. In addition, each line supports output logging. The SET MUXLn LOG command enables logging on a line: SET MUXLn filename log output of line n to filename The SET MUXLn NOLOG command disables logging and closes the open log file, if any. 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 MUX 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 controller (MUX) implements these registers: name size comments STA[0:31] 6 status, lines 0 to 31 RBUF[0:31] 8 receive buffer, lines 0 to 31 XBUF[0:31] 8 transmit buffer, lines 0 to 31 FLAGS[0:127] 1 line flags, 0 to 3 for line 0, 4 to 7 for line 1, etc SCAN 7 scanner current flag number SLCK 1 scanner locked flag TPS 8 character polls per second The lines (MUXL) implements these registers: name size comments TIME[0:31] 24 transmit time, lines 0 to 31 The terminal multiplexor does not support save and restore. All open connections are lost when the simulator shuts down or MUX is detached. 2.10 Project Genie Drum (DRM) The Project Genie drum (DRM) implements these registers: name size comments DA 19 drum address CA 16 core address WC 14 word count PAR 12 cumulative sector parity RW 1 read/write flag ERR 1 error flag STA 2 drum state FTIME 24 channel program fetch time XTIME 24 interword transfer time 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 drum not ready Drum data files are buffered in memory; therefore, end of file and OS I/O errors cannot occur. Unlike conventional SDS 940 devices, the Project Genie drum does not use a channel. 2.11 Rapid Access (fixed head) Disk (RAD) The rapid access disk (RAD) implements these registers: name size comments DA 15 disk address SA 6 sector word address BP 1 sector byte pointer XFR 1 data transfer flag NOBD 1 inhibit increment across track ERR 1 error flag CHAN 4 active channel PROT 8 write protect switches TIME 24 interval between halfword transfers 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 The rapid access disk is buffered in memory; end of file and OS I/O errors cannot occur. By default, the rapid access disk is assigned to channel E. 2.12 Moving Head Disk (DSK) DSK options include the ability to make the drive write enabled or write locked: SET RAD LOCKED set write locked SET RAD WRITEENABLED set write enabled The moving head disk implements these registers: name size comments BUF[0:63] 8 transfer buffer BPTR 9 buffer pointer BLNT 9 buffer length DA 21 disk address INST 24 disk instruction XFR 1 data transfer flag ERR 1 error flag CHAN 4 active channel WTIME 24 interval between character transfers STIME 24 seek interval 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 By default, the moving head disk is assigned to channel F. 2.13 Magnetic Tape (MT) MT options include the ability to make units write enabled 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 implements these registers: name size comments BUF[0:131071] 8 transfer buffer BPTR 18 buffer pointer BLNT 18 buffer length XFR 1 data transfer flag CHAN 4 active channel INST 24 magtape instruction EOF 1 end-of-file flag GAP 1 inter-record gap flag SKIP 1 skip data flag CTIME 24 interval between character transfers GTIME 24 gap interval POS[0:7] 32 position, drives 0:7 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 end of tape OS I/O error end of tape; if STOP_IOE, stop By default, the magnetic tape is assigned to channel W. 2.13 Symbolic Display and Input The SDS 940 simulator implements symbolic display and input. Display is controlled by command line switches: -a display as ASCII character -c display as four character SDS 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 four character SDS string alphabetic instruction mnemonic numeric octal number Instruction input uses (more or less) standard SDS 940 assembler syntax. There are eight instruction classes: class operands examples comments no operand none EIR POP (prog op) op,addr{,tag} POP 66,100 I/O addr{,tag} EOM 1266 mem reference addr{,tag} LDA 400,2 STA* 300 indirect addr reg change op op op... CLA CLB opcodes OR shift cnt{,tag} LSH 10 chan command chan ALC W chan test chan CAT Y All numbers are octal. Channel designators can be alphabetic (W, Y, C, D, E, F, G, H) or numeric (0-7). Tags must be 0-7, with 2 indicating indexing.