[Coco] DCD's (Good Old) 68HC08 MCU Is Going Strong

[Boisy Pitre]

Well, right off hand, the lack of a Y and U register would make porting a nightmare, not to mention grow the code size. There may also be differences in instruction side effects that I’m not aware of. Plus, the system call ABI would have to be changed to accommodate the lack of these registers.

OS-9 is fundamentallly welded to the 6809 microprocessor’s architecture. Trying to port it over to a processor with a subset of the registers and instructions would result in something that is not binary compatible with existing programs, and that’s just for starters.

On Apr 9, 2014, at 2:46 PM, billg999 at cs.uofs.edu wrote:

>> I’ve wondered the same thing. Imagine how OS-9/6809 could be resurrected
>> to run on those!
>> 
> 
> Why not port it to the 6808?
> 
> bill
> 
> 
> 
> 
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