Code license:	GNU General Public License v3
Labels:	pep8, assembler, simulator, ComputerSystems, J.StanleyWarford, Jones, Bartlett, pep8, pep8, pep8.1

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Pep812Lin.tar.gz Pep812Mac.zip Pep812Win.zip

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Project owners:
	Stan.Warford, chris.dimpfl

Pep/8 Assembler and Simulator

This repository is for version 8.1 of the source code of the Pep/8 simulator and assembler for use with the textbook Computer Systems. The application is written in C++, is GUI-based, and is compiled with the Qt 4 development environment using the Qt Creator IDE available from Nokia at http://www.qtsoftware.com/downloads/ .

Current version

The current version of the Pep/8 assembler and simulator is 8.1.2. See what's new with this release.

Contact

Please send comments, bug reports, and feature requests to Stan Warford.

Textbooks

J. Stanley Warford, Computer Systems, fourth edition, Jones & Bartlett, Publishers, 2010, ISBN 978-0-7637-7144-7. See this errata page for printing errors in the fourth edition of the textbook. Please send textbook errata not yet listed to Stan Warford.

Pep/8 is also used in Computer Science Illuminated, Fourth Edition, by Nell Dale and John Lewis, Jones & Bartlett, Publishers, 2011, ISBN 978-0-7637-7646-6.

Pep/8 at SIGCSE 2010

A paper titled The Pep/8 Memory Tracer: Visualizing Activation Records on the Run-Time Stack will be presented at SIGCSE 2010, the 41st ACM Technical Symposium on Computer Science Education in Milwaukee, WI. The conference runs from March 10 - 13, and the paper is scheduled for the session on Computer Organization on Friday, March 12 between 3:30 and 4:45 p.m. Conference details are here. If you will be there we hope to see you, as we like to meet with users of Pep/8.

Downloads

The Pep/8 computer is a 16-bit complex instruction set computer (CISC). It is designed to teach computer architecture and assembly language programming principles. Its 39 instructions are based on an expanding opcode and are either unary (one byte) or nonunary (three bytes). The eight addressing modes and eight dot commands are designed for straighforward translation between C/C++ and assembly language.

The Downloads section of this site contains builds and source code for the support software for the textbook. In addition to the assembler and simulator hosted at this site, the Downloads section includes a CPU simulator and a cache simulator. Here is a summary of the Downloads software.

Pep/8 assembler and simulator

The assembler features an integrated text editor, error messages in red type that are inserted within the source code at the place where the error is detected, student-friendly machine language object code in hexadecimal format, the ability to code directly in machine language, bypassing the assembler, and the ability to redefine the mnemonics for the unimplemented opcodes that trigger synchronous traps.

The simulator features simulated ROM that is not altered by store instructions, a small operating system burned into simulated ROM that includes a loader and a trap handler system, an integrated debugger that allows for break points, single step execution, CPU tracing, and memory tracing, the option to trace an application, the loader, or the operating system, the ability to recover from endless loops, and the ability to modify the operating system by designing new trap handlers for the unimplemented opcodes.

Download the source code and the Qt Creator IDE available from Nokia. Choose the LPGL / Free version. Launch Qt Creator and open the pep8-1.pro project file. When you click the build icon, Qt Creator will automatically construct the makefile and build the application.