[Coco] Learning assembly for the Color Computer

[Gene Heskett]

On Thursday 14 April 2016 16:56:35 Robert Gault wrote:

Robert, I just tried to answer you PM, but your server rejected mine 
instantly because of un-named abuse.  I'll try and send it via the other 
server I have access to.

> I'll add a book to Bill's list. It may or may not be on the Internet
> for download.
>
> "6809 Assembly Language Programming" by Lance A. Leventhal,
> Osborne/McGraw-Hill, 1981, ISBN 0-931988-35-7
>
> The platform on which you learn programming will make all the
> difference in the world. It will most likely be either a real Coco or
> an emulator, but the two real choices are for use under Basic or OS-9.
> When you program for Basic, you have essentially no ability to easily
> interact with the hardware unless you carefully read the Unravelled
> series to find useful access points in the ROMs. Of course other books
> written for programming on the Coco will tell you about those access
> points.
> When you program for OS-9 (NitrOS-9), it is easy to access all the
> hardware as OS-9 include drivers that provide I/O to the screen, disk,
> tape, printer, etc. The catch is that it is a much steeper learning
> curve required to learn to use OS-9 in addition to learning assembly
> language. :)
>
> In short, you will need to do more or less the same thing you did to
> learn writing programs for Basic on the Coco. Write the simplest and
> shortest program you can think of, probably copying one you got from a
> magazine or book. Do that until it becomes second nature.
> Eventually you will remember the structure required for ml programming
> and can easily lookup the op-codes needed. Continue and you will
> remember the codes themselves. They are all based on the limited
> number of registers contained in the 6809 and 6309 cpu.
>
> Personally, I think using Disk EDTASM to learn programming for use
> with the Basic ROMs is the best route for a beginner. That's because
> the package contains an editor/assembler for writing and compiling
> code as well as Zbug. Zbug gives you direct access to memory where you
> can read the ROM code and test your own code. Zbug permits
> step-by-step progress through your code while watching what happens to
> the registers and memory.
>
> Robert


Cheers, Gene Heskett
-- 
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