[Coco] CP/M emulator for OS-9

[Al Hartman]

Back in the day, there were several CP/M add-ons for the Coco. I wanted 
one, but never bought one.


I guess today, one could build one of Grant's Z-80 based boards and just 
attach it to a Coco as a terminal and keyboard. Though, you'd want an 80 
column card too.


I've been meaning to get a Microsoft Z-80 Softcard (or Clone) for my 
Apple ][gs system. I have CP/M for my Model 4D.


It's really great that you have CP/M running as fast as it does on a 
Coco.


How much faster could it get if it were pure 6309 only?


-[ Al ]-

On Tue, Apr 07, 2015 at 07:58 AM, Cocodemus wrote:

> For those interested I have optimized even further the code. I made a 
> video for my fellow brazilians (its in portuguese) but you can see how 
> it works.
>
> Only runs in Level 2 preferably on a 6309 but is full 6809. Just mount 
> the disk and run the lowercase script in each disk, like turbo, zork, 
> etc.
>
>  In the video i have copied them all to my hdd. But keep in mind some 
> applications like turbo pascal will hang when displaying a hdd 
> directory. Too many free bytes to display. It runs fine from disk 
> though.
>
>>  https://www.youtube.com/watch?v=6viIVxViKvE
>>
>
> Source code and sample disks:
>
>>
>> 
>> https://sites.google.com/site/tandycocoloco/dropbox/CPM_Emulator_for_OS-9L26809-v1.1.zip?attredirects=0&d=1
>>
>
> For those interested in details the cpm code is less than 8KB, leaving 
> 56KB for the application. The memory used is the level2 "flat mode", 
> making a direct map to z-80 memory addresses. The variables  (DP and U 
> register) are moved to the top of the memory leaving the z-80 
> addresses intact. Support routines and minimal CP/M routines are 
> provided through a software trap mechanism: memory $ffff. This tells 
> when exiting emulated environment to os-9 real calls.
>
> There are several LUT's, each instruction is fetched and executed. All 
> z-80 registers are memory positions. LUTs are used to flag conversion 
> and parity calculations.
>
> You can use 3 terminals: native os-9( you need to reconfigure the cp/m 
> software to use os-9 escape codes) or Dec vt-52 (-v option) or kaypro 
> ii (-k option). Most of the cp/m available software are for the two.
>
> Enjoy
>
> -- 
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> Coco at maltedmedia.com
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>