[hatari-devel] possible sound regression: Erik

[npomarede at corp.free.fr]

On Sun, 25 Jul 2010, npomarede at corp.free.fr wrote:

>> I tried Pompey Pirates 111 but there is also a crack by the Replicants
>> available.  In case you can't track it down I can zip you both versions
>> up.
>> 
>> Matthias
>
> I just got a copy of PP 111, but it crashes when starting game under steem 
> (works under hatari). Could you send me your zipped .st file so I can compare 
> the results under steem ?
>
> Nicolas

Hello,

I committed a fix for this. In fact, the game is buggy, it uses timer B in 
delay mode to play samples, but when there're no sample to play, it does :

MOVE.B #$06,$fffffa21
MOVE.B #$1e,$fffffa1b

but from the rest of the code, I guess it wanted to do :

MOVE.B #$06,$fffffa1b
MOVE.B #$1e,$fffffa21

(regs are inverted !)

This means on a real ST the timer B is set in "pulse width mode", which is 
nearly never used by any program as this is used to measure a signal on an 
external port connected to the mfp. This clearly looks like a coding 
error and it's quite lucky some sound are produced at the correct rate.

Still, the timer needs to keep running under Hatari when in pulse mode, so 
I fixed it (it was previously stopped, and the game never started it 
again).

We should now have the same (ugly) digi sounds as under Steem :)

Nicolas