A program designed to exhaustively test expansion memory on an Apple IIGS.
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A program designed to exhaustively test expansion memory on an Apple IIGS.

Boot up and running a quick test


There is a full manual here http://goo.gl/NiKJTH


Disk images are available on the project releases page. https://github.com/digarok/MiniMemoryTester/releases

You can transfer them to a 3.5" or 5.25" disk using ADT Pro or you can run it from your modern SD storage systems.


You can build it yourself using the make_po.sh Bash script under Linux or OSX. It should be trivial to write an approximate BAT or Powershell for Windows, if that is what you are using. Note - You need to edit the following lines in the make_bootable script:


You will obviously also need those two tools on your system. They are available here:

Merlin32 - 65c816 Assembler

CADIUS - Command line disk image tool

About the code

Historical Context:

This grew out of a much simpler memory tester I had thrown together earlier in 2015. At one point, I started working with an Apple II hardware vendor to include their feedback as feature enhancements which eventually caused a large rewrite to support a more robust configuration. There are some hacks and magic sprinkled in, but I tried to keep it pretty sane.

Some of the code paths for the testing engine are a bit generic, at the expense of speed, but to make the code more managable (for me!) Other parts are, perhaps, oddly organize but with a mind on keeping overall test loops relatively tight.
Overall, this program favors configurability and reusable code, over speed. There's also not much thought to stability, but I wanted to allow the user to try to test their RAM as they see fit.

Technical Context:

Large portions of this program are written in one of the two cpu modes:

m=1 (short) x=0 (long)


m=0 (long) x=0 (long)

The 8-bit test modes, in particular, are written with a short accumulator, but long index registers. This way it can easily scan a bank of memory using the X register from 0000 to FFFF. Likewise, when running 16-bit test modes, we write 16 bit values using a long accumulator, and still using long index registers. However, we also increment or decrement by two, since it writes two bytes at a time with a long accumulator.

TestInit function is where the "BEGIN TEST" code starts.

Again, see the manual at the top for the full description of the software and usage.