[Coco] [CoCo] Success with Color Forth!

[Stephen Pereira]

Hello all,

I have been typing in the source code for the Color Forth ROM cartridge, in hope of changing the memory location and getting the code to run in the lower 32K of memory in my CoCo 3.  Both the Color Forth ROM file and the Color Forth manual are available online.  The Color Forth manual contains a source listing for the kernal system, plus 24 additional screens of code to load in after the kernal is up and running.

This past weekend, I completed my typing, and I spent Saturday getting the code to assemble on my CoCo 3 with HDBDOS, Drivewire, and Disk EDTASM (modified to work with HDBDOS and Drivewire by Robert Gault).

I found a bunch of typing errors, but I also found that the listing had a number of mnemonics that EDTASM did not understand.  I had to change CPX to CMPX, STAB to STB, both in a few instances,  and in one instance I had to change CMPB 0,Y+ to be CMPB ,Y+ because EDTASM was complaining of an illegal operand.

I finally achieved a file that assembles with only 4 warnings that a long branch is not needed.

I also tried to relocate the code.  I changed PRGBGN from $C000 to $5800, and I changed BRAM from $0620 to $2000.  I could LOADM this code, and it came up when I EXECed it.  Once it was up, I could type VLIST and see all the words scroll by.  I could type both WARM and COLD and see the code restart.  When I actually attempted to do something like 1 2 3 + + . then the system blew up.

A couple of folks on this list have been communicating with me about this project.  I contacted one of them with my progress and asked for his advice.  He was kind enough to take a look and found 3 typos that I still had.  With those fixed, I now have the Color Forth kernal up and running!  Thanks a million Brett!

I will gladly send a copy of the Color Forth source code to anyone who is interested.  Just send me a message off list, and I’ll respond with the file attached.

Next, I’ll be drawing up a memory map and learning more about the internal working of Color Forth so I can ignore the cassette I/O and hopefully be able to load and save new screens of code with LOADM and SAVEM.

Thanks for listening!

smp
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Stephen M. Pereira
Bedford, NH  03110
KB1SXE