Vectrex Diary

Working from Visual Studio 2010 for Vectrex programs

2012-02-23T06:10:28Z

For many years I’ve been working with Visual Studio as my main development IDE. I’ve seen many incarnations, since Visual C++ 2.0, through VC++ 2.1, 2.2, 4.0-4.2 and from there also Visual Basic 5.0, 6.0, and Visual Studio.NET, 2003, Visual Studio 2005, 2008 and now Visual Studio 2010 with “Dev11” gleaning at the horizon. Knowing your development thoroughly is a great advantage. I ‘d rather not go back to other editors and/or environments.

That’s why I have created a Makefile project for Visual C++ and hooked up the AS09 compiler for 6809 code.

Preparing the project

You will need to download Visual C++ 2010 Express to do this. If you’re spoiled like me, you might just have a paid version of Visual Studio 2010, which should include Visual C++.

After choosing the Makefile project you can choose a filename for your project. I have named it HelloWorld

A wizard will start that allows you to enter lots of information. Simply press Finish, as you can set this up in another dialog (with some more space for editing).

At the Solution Explorer, you will see the new HelloWorld project. Right-click it and choose Properties.

Go to the Configuration Properties, NMake at the left tree and fill the three command-lines with the following:

"C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\bin\nmake.exe" /f hello.mak BUILD=Debug all
"C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\bin\nmake.exe" /f hello.mak BUILD=Debug all
"C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\bin\nmake.exe" /f hello.mak BUILD=Debug clean

This means that we will have a hello.mak NMAKE file for our compiler to use. There will be two configurations for building, rebuilding (the same for now) and cleaning.

Set the Output to hello.bin. That is the name of the file that we will be producing.

Add a new text file “hello.mak” to the project. You will also need to include the hello.asm file in the root of the project. The result looks like this:

Editing the make file

Open the hello.mak file and copy the following text in it:

.SOURCE :  
.SUFFIXES : .asm .bin
 
AS="C:\Program Files (x86)\AS09\AS09.exe"
ASFLAGS=-cgiv -h0
 
target = hello.bin
objects = hello.bin
 
.asm.bin:
	$(AS) $(ASFLAGS) -l$(BUILD)\$*.lst -o$(BUILD)\$@ $<
 
all: $(objects)
 
clean:
	del $(BUILD)\*.lst
	del $(BUILD)\*.dbg
	del $(BUILD)\$(target)

Explaining the contents of the make file

Let’s take a short look at the individual elements.

.SOURCE is not used, but indicates subdirectories where source code might be located. .SUFFIXES lists the extensions of files that while be recognized.

AS is a shorthand macro for the compiler and the ASFLAGS for the compiler flags.

The -cgiv flags means that the compiler will:

output cycles counts per instruction (c flag, which is relevant in combination with the l flag)
generate debug information (in a separate .dbg file)
be case-insensitive
be verbose in its output

The flag –h0 indicates infinite page length for the generated listing file hello.lst.

Next are the target and objects, which indicate the thing we will produce (target) and which things (objects) are needed to create the target. In this simple case this is the same. More complex scenarios might have other objects accumulating into the target.

The line .asm.bin: and the line after that is a inference rule that tells NMake how to create a .bin file from a .asm file. In this case it is accomplished by:

$(AS) construct the compiler command
$(ASFLAGS) adds the flags to the command
with a listing flag –l at the location $(BUILD)\$*.lst
The last part will expand to something like DEBUG\hello.lst, because the macro BUILD holds the current build configuration (DEBUG or RELEASE) and $* is the current file (from the rule) without an extension (so hello.asm becomes simple).
at the output $(BUILD)\$@ as specified by the –o flag
This will expand to DEBUG\hello.bin, because $@ is the target of the rule (in this case the .bin that needs to be created)
with input file $< that holds the complete filename that is the lefthand side of the rule (hello.asm)

The final sections indicate the all and clean configurations. All is the build configuration that is used for both a normal Build and the Build All. Since we have only one project the two use the same “all” configuration. It will build all objects are indicated by the objects= line. The clean configuration will run three delete commands that get rid of all .lst, .dbg files and the target.

Building the solution

You can now build the project from the Build menu, Build Solution (shortcut is Ctrl+Shift+B). The makefile project will run the NMake utility and feed it the hello.mak file. plus the value “all” to build. The result should be something like this in the Output window:

1> Microsoft (R) Program Maintenance Utility Version 10.00.30319.01
1> Copyright (C) Microsoft Corporation. All rights reserved.
1>
1> "C:\Program Files (x86)\AS09\AS09.exe" -cgiv -h0 -lDebug\hello.lst -oDebug\hello.bin hello.asm
1> AS09 Assembler for M6809 [1.42]. Copyright 1994-2007, Frank A. Kingswood
1>
1> Optimization enabled.
1> Pass 1.
1> 20 lines read, no errors in pass 1.
1> Pass 2.
1> No errors in pass 2.
1> Checking binary file boundaries.
1> Writing binary file "Debug\hello.bin".
1> Wrote binary from address $0000 through $0022.
1> Total size 35 bytes.
1>
1> Reading from file "hello.asm"
1>
1> Reading from file "hello.asm"
========== Build: 1 succeeded, 0 failed, 0 up-to-date, 0 skipped ==========

Clicking the Show All Files button at the top of the Solution Explorer reveals the contents of the Debug folder:

where all output is located. Running Clean solution from the Build menu will get rid of the output of the build proces.

More information can be found at the MSDN website.

Hello World with 6809 assembler language

2012-02-22T17:25:00Z

The first thing I did after finding the developer information is skim through the Introductionary Tutorial by Christopher L. Tumbler. I want to get a feel for the assembly language, and the way the games for the Vectrex are created. At first glance the code for the 6809 seems reasonably close to the 6502. There are 16-bit registers and instructions that make use of those. Branching is possible with the relative short jump (plus or minus 127 offsets), but also long jumps which take an additional byte.

The code for a typical Hello World program looks like this:

ORG $0000

; Magic Init Block
FCB $67,$20
FCC "GCE XXXX"
FCB $80
FDB music
FDB $f850
FDB $30b8
FCC "SIMPLE"
FCB $80,$0

start:
bra start

music:
FDB $fee8
FDB $feb6
FCB $0,$80
FCB $0,$80

Notice the magic initialization block that is needed for a Vectrex program. The program loops infinitely and plays no music.

I want to get this simple program to compile. So, I started searching for compilers:

AS09 at http://www.kingswood-consulting.co.uk/assemblers/
GCC6809 (C compiler for 6809, so not useful for this code fragment)

I unpacked the AS09 1.42 compiler and copied the Simple.asm file (with the contents above) to the directory.
Compile the source with:

as09.exe simple.asm

As it seems the compiler has some issues with upper case mnemonics. Normally the –i switch should make the compiler case-insensitive, but this doesn’t seem to happen. I’ve contacted Frank Kingswood about this. Changing the ORG, FCB, FCC and FDB to lower-case does the trick for now.

The result of the compilation is a simple.bin binary file that you can run on an emulator like MESS. The syntax for running this is:

mess64.exe vectrex –cart roms\vectrex\simple.bin

where I have run this command from the command-line at the MESS root directory. My roms are stored in the subdirectory roms\vectrex. The required boot rom for Vectrex is also located in that folder.

I have also stumbled on the source code for VecThrust at the website of Ville. This will be interesting later on.

Scavenging the internet for Vectrex information

2012-02-20T15:37:58Z

These are the first interesting links that I found roaming the Internet:

http://en.wikipedia.org/wiki/Vectrex
The Wikipedia page for the Vectrex. Has some history and tells about the working of the device and the 3D imager and light pen.
http://www.vectrex.biz/
Richard created the VecMulti and VecFlash cartridges. The first one seems to be able to host different kinds of cartridges, as it mentions 64K bank-switched games. Uses a Micro-SD card as the backing store.

The VecFlash is discontinued and seems a precursor to the VecMulti.
http://www.vectrex.co.uk/
Has information on the VecDev developer cartridge and some modifications like the resetting after uploading a game to the cartridge. Cartridge is supposed to be available from Vectrex.biz but it is not mentioned there I think.
Also, under Documents/Data sheets it has a lot of technical information on the electronics inside the Vectrex. Most importantly I found the Vectrex FAQ here, plus the programming manuals and a tutorial.
Vectrex museum http://www.vectrexmuseum.com/
Complete overview of the original, prototype and homebrew games. Interesting news section. Also has a section with programming documentation.

A new thing

2012-02-19T20:11:19Z

Time to try something new. I want to see if I can commit to write blog posts and keep some form of diary as I go about creating a blog on building a Vectrex emulator and maybe a game in the process. Usually I try to find out things on some topic and explore everything, but never get around to writing about it. I will try to do it the other way around. It’s an experiment, but it’s worth a shot.

Initial goal formulation:

Create a modern Vectrex emulator for the managed .NET platform

So, with that said, time to do some initial high-level planning (aka lying) and summarize some things that need to be done.

Find general information on the Vectrex
Find technical and developer information
Find out what the technical components of the Vectrex are
Understand the way the Vectrex works
Understand the programming language for the CPU
Understand the boot process
Emulate CPU, memory and electronics for video
Try to get visuals from the vector graphics
Do the audio, controls and other hardware
… (we’ll see where we stand when we get here)

To make this work I will try to brain dump instead of going for complete, error-free, correct, article-like writing. That means it will be a diary of progressing insights. You’ve been warned.

On with the experiment.