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THE UNIVERSITY OF MICHIGAN Memorandum PDP-8 SIMULATOR

IP.com Disclosure Number: IPCOM000128416D
Original Publication Date: 1967-Jul-01
Included in the Prior Art Database: 2005-Sep-15
Document File: 5 page(s) / 19K

Publishing Venue

Software Patent Institute

Related People

Lundstrom, Stephen F.: AUTHOR [+4]

Abstract

This program, written in PDP-7 code, simulates a PDP-8 computer, i.e., it will execute a program written in PDP-8 binary code.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 54% of the total text.

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THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

THE UNIVERSITY OF MICHIGAN Memorandum PDP-8 SIMULATOR

Stephen F. Lundstrom Dianne Callan

CONCOMP: Research in Conversational Use of Computers
F. H. Westervelt, Director ORA Project 07449

supported by: DEPARTMENT OF DEFENSE ADVANCED RESEARCH PROJECTS AGENCY WASHINGTON, D.C.

CONTRACT NO. DA-49-083 OSA-3050 ARPA ORDER NO. 716

administered through: OFFICE OF RESEARCH ADMINISTRATION ANN ARBOR July 1967

ABSTRACT

This program, written in PDP-7 code, simulates a PDP-8 computer, i.e., it will execute a program written in PDP-8 binary code.

1. REQUIREMENTS
1.1 Storage

000008 - 114008

The PDP-8 program is stored in 00028 - 77778. PDP-8 locations 0 and 1 are placed in locations ADD0 and ADD1 respectively, since these locations are used for interrupt control.

The simulation (PDP-7) program is stored in 100058 - 114008.

1.2 Subprograms and Subroutines

Standard RIM and PDP-7 binary loaders PDP-8 binary tape of the program to be simulated

University of Michigan Page 1 Jul 01, 1967

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THE UNIVERSITY OF MICHIGAN Memorandum PDP-8 SIMULATOR

2. USAGE

2.1 Loading

Normal binary tape loading procedure for main program.

The PDP-8 tape may be loaded automatically (when the program is started at RESET (10422) or with SW4=1.)

2.2 Calling Sequence

Not applicable

2.3 Switch Settings

SWO = Continue

SW1 = Load Address from Switch Register SW2 = Examine location in Memory
SW3 = Start(clears simulated AC and all flags)

SW4 = Load a new tape and start over SW5 = Deposit the contents of the PDP-8 Switch Register. When the simulation is "running" a panel dump on JMP and JMS results.

SW6-17 = PDP-8 Switch Register.

2.4 Start-up and/or Entry

Starting address = 10422. When started at this location, low core is initialized and a new tape is loaded.

After loading this program and placing PDP-8 tape in the reader, press CONTINUE twice.

For a restart without automatically loading a tape, set PDP-7 Address Switches to location 10376 and press START.

2.5 Errors in Usage

The following message is printed when a checksum error occurs in the PDP-8 binary loader:

E #XXXXXX

University of Michigan Page 2 Jul 01, 1967

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THE UNIVERSITY OF MICHIGAN Memorandum PDP-8 SIMULATOR

where # is the error number, in this case 1, indicating a checksum error, and XXXXXX is the contents of the accumulator.

2.6 Recovery from such Errors

Reload the PDP-8- simulated tape.

3. RESTRICTIONS

3.1 IOT Instructions

Certain PDP-8 IOT instructions do not have exactly equivalent PDP-7 instructions, and therefore the PDP-7 instructions that are most similar are substituted. The instructions are: PDP-8 PDP-7

KCC 6032 KRB followed by CLA KRS 6034 KRB 700312 KRB 6036 KRB 700312 TPC 6044 TLS 700406 IOT and IOF are not executed by the simulator but are handled in an appropriate manner.

The remaining IOT's are mapped into PDP-7 IOT's as follows:

6XXY becomes 70XX0Y

3.2 Timing

The approximate simulation ratio is 100 to 1.

3.3 EAE

This si...