View source for Sxgo

[[Image:sxgo_screenshot.png|right]]
sxgo is my C++-based, soon-to-be open source SX28 emulator.

I'm developing this emulator for my private purposes (mainly testing complex SX assembly projects before doing a burn-and-watch-the-leds-blink-cycle). The emulator is quite spartan and certainly not as versatile as the already existing and excellent [http://forums.parallax.com/forums/default.aspx?f=7&m=53539 sxsim for windows]. In its simplicity, it's got two advantages though: 
* It is portable (I develop on Windows and Ubuntu Linux and have it running on both)
* It is fast. On my 2.66 Ghz machine it runs at about 70 MIPS. Close to real time for most SX projects.


==Features==
===supported===
* breakpoints
* single step
* run freely mode (which is interruptable from the UI)
* ram window
* watch window
* Outline window, showing clickable code labels

===not supported===
* anything but the SX28
* the option to map the W register onto address 0
* input/output panel
* wakeup/brownout
* any of the "undocumented instructions"
* and much, much more...

==Status==
The GUI is quite rough around the edges and it's probably going to be quite easy to break this program. Test coverage has been limited to the listings that I write myself. This means that:
* the simulator could crash
* there may be a bug in some of the sx instruction implementations. Getting the correct Carry-flag behaviour has proven to be ''interesting'', to say the least.

== Support ==
Ah. There's one catch: No guarantees. I could drop this project tomorrow. My dabbling in SXes is pure hobby-work and although I'm a professional programmer, this particular program is just an exercise on the side.

==Python module==
Sxgo comes with a [http://www.python.org/ python] module, that allows a programmer to create extensive test-scripts. This feature is one that I'm currently putting much effort into, since complex SX firmwares tend to need some automated testing and python scripts are a very convenient way to do such a thing.

I have made no provisions to install this module into a python environment, since python is one of those areas that I have actually very little experience with. I believe though, that simply copying the module (.pyd file for windows, .so file for linux) to the right location (python scripts directory) should probably do the trick. I myself always use the module in the same directory as the test-scripts and that seems to work too...

Currently, the python module and the emulator GUI are completely separate programs: you can either write a python script to run your SX listings in or watch them in the GUI, not both.

As a teaser, [[sxsim test python script|here's a python script]] that runs a [[thermostat listing file|specific SX assembly program]] (one that reads a SPI temperature sensor and outputs the temperature to a serial port as ascii text). The script breaks the program execution to insert 'simulated' inputs and to retreive the outputs and write them to the PC console output.



== The sources ==
I '''do intend''' to release the sources to this program. It's just that I need things cleaned up a little (mainly adding license information and big fat disclaimers to all the source-files). I intend to release the whole source under the [http://www.boost.org/LICENSE_1_0.txt boost license], which is a 'BSD-like' non-viral open source license. See also [http://www.boost.org/users/license.html this explanation].

But I have to warn anybody that is interested in the sources beforehand: If you think that C++ templates are evil, you won't like reading the sources. Even I think that the current implementation of the instruction decoder is convoluted and requires unhealthy amounts of caffeine to comprehend.

Since I originally intended this program for my personal use only, the source code documentation (comments) are only there to get me started on the project again after a month of real work.