[Coco] Reading keyboard input without basic

[Arthur Flexser]

The counterargument there is that Tandy was extremely stingy about
providing documented entry points to useful ROM routines, so in many cases
software authors were forced to choose between using undocumented ones or
reinventing the wheel.  Anyone who modified their Color Basic ROM without
preserving the major undocumented entry points (a somewhat difficult thing
to do, since there is no free space available in that ROM) would
encountered compatibility problems with a lot of software, and deserve it.

Art

On Wed, Feb 10, 2016 at 1:44 PM, Dave Philipsen <dave at davebiz.com> wrote:

> I agree.  It would just be good practice to do so even if for just the
> CoCo because it is possible that someone out there has some sort of custom
> ROM.  But as long as they've followed the rules for the vectors to the ROM
> routines then the code will always work as JSR [$A000]  while it may not
> work on a custom ROM with the direct JSR.
>
> Dave
>
>
> On 2/10/2016 9:10 AM, John W. Linville wrote:
>
>> On Wed, Feb 10, 2016 at 08:06:56AM -0500, Arthur Flexser wrote:
>>
>>> The one at $A1C1 also has a documented vector and
>>> so may also be called by JSR [$A000] if memory serves me correctly.  (Or
>>> maybe it's $A002, too lazy to look it up.)  But there's no particular
>>> advantage to using that, since we now know that there will be no future
>>> Basic version where a direct call to the routine won't work because the
>>> entry point has changed.
>>>
>> Au contrair!  If you use the JSR [$A000] then the code will work on
>> the Dragon as well, without modification.
>>
>> John
>>
>
>
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