[Freemint-list] [PATCH] Milan keyboard handler for ColdFire

[Vincent Rivière]

On 08/06/2016 08:16, Jo Even Skarstein wrote:
> Out of curiosity - what is the purpose of this patch? AFAICS this code
> is only compiled for the Milan.

True... At the moment :-)

Actually, FreeMiNT can hook the keyboard in 2 ways to do its advanced 
AKP stuff:

1) The Milan way. It is the simplest approach. Hook the undocumented 
"kbdvec" vector, which is present just before the pointer returned by 
Kbdvbase(). That vector is called for each IKBD byte related to the 
keyboard, exactly what FreeMiNT needs. But that vector is only available 
in TOS >= 2.x and EmuTOS. This is why FreeMiNT does not use it by default.

2) The ikbdsys way. This standard vector is called each time a byte is 
present on the keyboard ACIA. The handler needs to read the byte from 
the ACIA, and dispatch it to the right vector. This is what FreeMiNT 
does by default. Unfortunately, that callback needs to access the ACIA 
hardware, so it is not compatible with non-Atari hardware.
I noticed that FreeMiNT also hooks the main IKBD/MIDI ACIA vector at 
0x118. I still don't understand why FreeMiNT does that.

Since non-Atari hardware is only supported by EmuTOS (Amiga and ColdFire 
EVB) and FireTOS (ColdFire EVB), it is safe to always use the Milan way 
in that case. That will be the object of a future patch.

-- 
Vincent Rivière