Two menu screens from MENU.BAS: some of my favorite games from The Rainbow, and some of my favorite text-based games typed in from various books.

For the true retro experience, you should, of course, access files from the command line, typing DIR to see the disk, interpreting the very abbreviated filenames, and then using RUN or LOADM to start the program. For the full retro experience, everything should be on cassette tape!

But your friends may enjoy the retro gaming experience without having any idea how to start up the games. You could, of course, put a coffee-stained sheet with helpful command-line hints next to the computer. Or, you could use this BASIC program, that leverages Darren Atkinson’s CoCo SDC floppy disk emulator to provide a simple interface to your favorite games (Zip file, 8.4 KB) saved on both the SDC’s flash slots and on .DSK disk files.

You can have as many screens as you want. The more screens, the longer it will take to load, and the more screens you (or your friends) will have to cycle through to see everything. I meant this as an easy means of showing off my favorite games; it is not meant as a comprehensive listing of everything. For a more complex file browser, see Guillaume Major’s SDC Explorer.

As written, MENU.BAS requires the SDC, but it should be able to be modified to use other solutions that store programs in ways that they can be accessed from a BASIC program.

The program attempts to respond to whatever the user might do to choose a game. If they pick up one of the joysticks, it will start following that joystick; if they use the up or down arrow keys, it will respond to them; SHIFT-up and SHIFT-down will move to the top and bottom, respectively. If they type the number corresponding to a game, the pointer will jump directly to that game.

Both lines 1600 and 2100 start new subroutines.¹ Line 1600 is a subroutine to read each joystick’s vertical value. If the new value doesn’t match the old value (RV or LV), the assumption is that the user has moved the joystick in order to choose a program. The vertical location of the joystick that was moved is converted to a position on the screen and then returned in NC (New Choice).

The subroutine at 2100 initializes the joystick and the screen (which I’ve removed from the sample above to make the new choice easier to see) and then, starting at 2180, begins the loop to check for new input.

1. It looks at the joystick buttons; if either is pressed, a choice has been made.
2. It checks the keyboard. If a key is pressed along the top keyboard row (the numbers 1 through 9, then 0, then a colon, then a dash), that’s assumed to be the number of the user’s choice, with 0 standing in for ten, a colon for eleven, and a dash for twelve. The up and down arrows adjust the choice up or down by one, and SHIFT-up (95) or SHIFT-down (91) adjust to the top or bottom. IC is the variable for Item Count, that is, the number of items on this screen. An ENTER (13), a CLEAR (12), or a SHIFT-CLEAR (92) return from the routine to either start the program (ENTER) or shift to a new screen (either form of CLEAR).
3. If there is no new choice, or if the new choice matches the old choice, it returns to the top of the input loop.
4. If there is a new choice, it clears the old choice and then goes to the display loop to display the new choice and start over again.

Choosing a game from the menu should thus be relatively easy for even a naive user to figure out, as long as they’re not afraid to touch the keyboard and/or joystick.

ENTER or a joystick’s fire button will start the chosen game. This may require a little more thought on the naive user’s part.

In a nod to OS-9, the CLEAR key switches between the various menu screens. SHIFT-CLEAR will move backwards through the screens.

The CLEAR key is code 12, and SHIFT-CLEAR is code 92.

Modify the names of the programs available by modifying the DATA statements in lines 3000 up. The first DATA line in each set is the title of the screen and the keyword SECTIONTITLE. Set the variable SC to the screen count—how many screens you want set up.

For subsequent lines:

1. The first item on each line is the displayed name of the program.
2. The second item is the file name if this is a BASIC or binary file; or the keyword MPI or FLASH if it’s a cartridge on the Multi-Pak Interface or a slot in the SDC’s flash memory;
3. The third item is a zero or one if this is a file, indicating a BASIC program (0) or a machine language program (1); a number from 1 to 3 if this is a cartridge, indicating which cartridge slot it’s in²; or a number from 1 to 7 indicating which flash memory slot the program is stored in on the SDC.

Each screen can have up to 12 programs. For example, here are the cartridges and one binary game that I keep on the first screen:

I don’t name the MPI slots, because I change those cartridges when I feel like it; the names of the cartridges are visible on the cartridge, in the MPI next to the Color Computer 2.

To make this program automatically start, you can create a STARTUP.CFG configuration file at the root of your SDHC card. The SDC will read this automatically, and load any .DSK files mentioned.

I store utilities on a UTILITY.DSK file that I automatically load into DRIVE 1. I save this program as AUTOEXEC.BAS on the utilities disk. The SDC sees that filename on one of the autoloaded .DSK virtual disks and runs it automatically after it loads the disks listed in STARTUP.CFG.

I store my favorite games on a .DSK file named COOL.DSK. These are all, or almost all, typed in from old Rainbow magazines, which is why the menu at the bottom says “CLEAR for Rainbow Games”.

“Rainbow Games” is the section title of the second screen, and the menu program automatically displays the next screen in the rotation.

Note that only UTILITY.DSK is required by the menu; the menu program will automatically try to load any other DSK referenced in the DATA lines onto drive 0.

I wrote this code using my own superBASIC. It made it a lot easier to keep the code readable. If you want to modify the code, you may find it easier to modify the simpler superBASIC source than to modify the running BASIC code. That said, one of my goals for superBASIC was that it create easily readable code, so you should be able to edit its BASIC just as easily as or even more easily than any other BASIC code you haven’t written yourself.

Here’s the code for the first screen, the one I used as an example above:

The code starts with “data maxlines 13”, which (a) marks the beginning of a section of DATA, and (b) will generate an error if there are more than 13 lines—1 for the section title and 12 for the displayed programs.

Among the features that using superBASIC enables are having a special holiday menu just for the holidays, and including a speech subroutine for using the Speech/Sound cartridge. I have a section of special code for including speech cartridge support, a Christmas menu, and a Fourth of July menu.

Near the fourth of July, I regenerate the BASIC using the “fourth” switch:

This turns on any code between #IFDEF fourth … #ENDIFDEF, which means those four programs now get their own screen and will display as the second screen.

And, of course, because I have a Speech/Sound cartridge, I’ve programmed it to speak “Greetings, Professor. Shall we play a game?” on startup.

There are three sections to enabling speech:

1. It includes the speech code, and then immediately speaks “Greetings, Professor.”
2. After it loads the screens, it speaks “Shall we play a gayme?”³
3. Finally, if loading a program from the MultiPak Interface, it will disable the speech code, because otherwise it might interfere with the cartridge code.

I use the following to generate a menu for my own CoCo:

This switches speech on in the final code, and saves it to AUTOEXEC.BAS, where it will be copied into UTILITY.DSK.