SYMON - A 6502 System Simulator

** NOTE: THIS IS ALPHA QUALITY SOFTWARE UNDER ACTIVE DEVELOPMENT. IT IS NOT YET FULLY FUNCTIONAL. IT MAY BE USEFUL, BUT IT IS NOT YET INTENDED TO BE USED BY ANYONE BUT DEVELOPERS. Feedback is welcome! **

Version: 0.2

Last Updated: 22 April, 2012

Copyright (c) 2008-2012 Seth J. Morabito web@loomcom.com

See the file COPYING for license.

1.0 About

Symon is a general purpose simulator for systems based on the NMOS Mostek 6502 microprocessor and compatibles. Symon is implemented in Java. It's core goals are accuracy, ease of development, clear documentation, and extensive test suites for validating correctness.

The initial goal is to simulate a system with an NMOS 6502 or CMOS 65C02 central processor; one or more 6522 VIAs; and one or more 6551 ACIAs. More functionality may be considered as time goes on.

2.0 Requirements

Java 1.5 or higher
Maven 2.0.x or higher (for building from source)
JUnit 4 or higher (for testing)

3.0 Usage

3.1 Building

To build Symon with Apache Maven, just type:

$ mvn package

Maven will build Symon, run unit tests, and produce a jar file in the 'target' directory containing the compiled simulator.

Symon is meant to be invoked directly from the jar file. To run with Java 1.5 or greater, just type:

$ jar -jar symon-0.1-jar-with-dependencies.jar

When Symon is running, you should be greeted by a simple graphical interface.

3.2 Loading A Program

Programs in the form of raw binary object files can be loaded directly into memory with the "Load" button.

Right now, all programs are loaded starting at addres $0300. After loading, the simulated CPU's reset vector is loaded with the values $00, $03, and the CPU is reset.

There is a simple sample program in the "samples" directory, for testing.

3.3 Running

After loading a program, clicking "Run" will start the simulator running at address $0300.

4.0 To Do

Interrupt handling!
UI needs a ton more polish.
Add a simple menu interface for common tasks.
More extensive testing.
Clean up JavaDoc.
Busses are defined by start address and length. Devices are defined by start address and end address. They should both use start/end address.
Implement CMOS 65C02 instructions and NMOS / CMOS mode flag.
Allow a flag to disable breaking to monitor on BRK.
Allow displaying ACIA status and dumping ACIA buffers, for debugging.

5.0 Licensing

Symon is free software. It is distributed under the MIT License. Please see the file 'COPYING' for full details of the license.

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