Keep it Secret, Keep it SEGA

The Trade Mark Security Signature (TMSS) was SEGA’s attempt to prevent unlicensed developers from releasing games for the Genesis / Mega Drive. Failing the TMSS check disables the Visual Display Processor (VDP). Passing the TMSS check displays this lovely screen:


TMSS check passed!

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Genesis Does Fibonacci

Can you think of a better way to spend a holiday than learning to write assembly language for a 26-year-old game console? I couldn’t, so I wrote a simple program for the SEGA Genesis. (Known as the Mega Drive outside North America.)

First, some tools are needed:

  • A decent text editor
  • An Assembler that produces M68000 machine code
  • A Genesis emulator with a built-in debugger

I tried to find these three tools for Mac OS X, my preferred platform. There are plenty of text editors available and the GNU assembler will run on just about anything, but I could not find a Genesis emulator for Mac OS X that has a built-in debugger. Phooey. Gotta use the right tool for the job, so it was time to dig out the old PC. Windows XP, Pentium 4. Let’s go!

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