Re: [hatari-devel] Happy birthday, Hatari!

[Laurent Sallafranque <laurent.sallafranque@xxxxxxx>]

That's an excellent and very interesting story.

Thanks a lot Thomas to share it for us.

I think it could be published in atari's forums at the birthday date for 
other atarian entousiasts.


3 Things for me :

- did I tell you that I'm working with the guy that wrote Pacifist ? We 
discovered each other in a meeting (my Atari sticker on my laptop helped 
to ice break and we started to speak about the atari world) ;)


- I've digged into my story with Hatari and I've just discovered that my 
collaboration with the team started in april 2008 (time flies so fast) :)


- For my part : I add 2 Atari ST and then a Falcon back in the old days. 
I left everything for studies and forgot the Atari world until march 
2008. I thought about emulation to take up with the Atari world. As a 
huge fan and user of Linux since ages, I searched for a compatible 
emulator for this OS. I found Hatari.  2 things I immediately liked were 
that it worked "out of the box" and the open source spirit of the project.

I started to play with the emulator by testing my old ST code and I 
tried some old code I wrote back in 1994 - 1995 for Falcon. The 68030 
part was working, but not the DSP part. I'm also a fan of Audio Fun 
Machine, and I started to dream that this program could revive one day.

That's about the time I told to myself I could contribute to Hatari 
development and I started by the DSP emulation (logical choice as I had 
never coded anything for the DSP before and I nearly didn't know 
anything about this chipset) ;)

My goal was to learn DSP coding, code a little demo for Falcon (I never 
released one in the old days, so it was not too late to code one), and 
improve Hatari. My first attemps to debug Patrice Mandin's code gave 
good results : after a few instructions fix, I managed to have the very 
first DSP Falcon demo running (it was SPHERE.PRG in june 2008) and 
3DWORLD.PRG a few days later.

After a long debugging (and more demos working), I started to implement 
the missing parts of the DSP emulation (DIV instruction, PORT C, 2 
channel Port-B, interrupts, Roundind code, ...) and more demos worked. 
But there was still no sound as the Falcon crossbar was not implemented. 
So I added this also and improved some other parts of the emulator here 
and there when I found something to fix.

I still take a lot of pleasure to code things for the Falcon and to code 
under Hatari here and there with all the team.

I really appreciate how you gave me your trust back in 2008 and the 
result is now great (the Falcon is better and better emulated after each 
version).

Thank you all.

Regards

Laurent

------> under is my very first mail to a certain Thothy, 02 april 2008 
17:55  <---------------------------

Hello Mr Thothy,

First of all, I want to thank you very much for Hatari, it's a great 
program.

I present me : my name is laurent Sallafranque, French (sorry for my 
poor English), 34 years old.
I used to have an Atari 520 stf, a 1040 ste ans a falcon030 (all sold 10 
years ago, shame on me !!)
I coded the "faith demo" with chuck in 1993 (I belonged to Dune demo 
group).

Why do I write you ? I would like to help (if it's possible) in the 
hatari project.

I fixed me a goal : to have AFP like programs work on hatari (DSP sound 
emulation working).
I've taken the last source release on CVS.

I've started to add DSP SSI emulation (nothing works better actually).
- DSP.H : I've added the SSI registers and bits definition (#define 
DSP_SSI_xxx )

- DSP.C : I've just added the initialization of SSI registers in 
DSP_Reset method.

- DSP_CPU.C : added the SSI interrupts in dsp_postexecute_interrupts 
method.
(not completely finished yet, I still have to emulate the interruption flag

I've also started to have a close look at the actual DSP code emulation :
- I activated the ENABLE_DSP_EMU flag, and started a few tests :

I realized that DSP registers are only read once at emulator 
initialization and never refreshed later.
But Dsp change the state of these registries each time datas are sent, 
receives, ...
I've added a method in ioMem.c (I should have added it in 
ioMem_tabFalcon I think) to refresh dsp host registers
when a IoMem_bget() is done in the dsp memory zone. I called it 
IoMem_RefreshDspIOMemory()

I've also added the 3 next lines into every IoMem_Xget() method (it's 
probably not the best way to do this, but I
don't know hatari code enough at this stage).
#if ENABLE_DSP_EMU
IoMem_RefreshDspIOMemory(addr);
#endif

I think it's a preliminary to get all the Dsp registry IO values before 
emulate them into the DSP.

I send you the few modification in the attached zip for if you find them 
interesting.

I would need to look closely to the dsp code and also help and open 
discussion with you all before doing more code.

Do you think I could help you in the hatari project ?

Sincerely,

Laurent

PS : I tried to compile the very last CVS version, I've got the 
following error :
dlgScreen.c: In function ‘Dialog_ScreenDlg’:
dlgScreen.c:176: erreur: ‘CNF_SCREEN’ has no member named ‘FrameSkips’
dlgScreen.c:184: erreur: ‘CNF_SCREEN’ has no member named ‘MonitorType’
dlgScreen.c:299: erreur: ‘CNF_SCREEN’ has no member named ‘FrameSkips’
dlgScreen.c:307: erreur: ‘CNF_SCREEN’ has no member named ‘MonitorType’
make[1]: *** [dlgScreen.o] Erreur 1

I've kept the cvs version from 3 days ago to make my tests.

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Le 21/03/2021 à 09:00, Thomas Huth a écrit :
>   at that point in time and that assembly syntax was quite
> different to the GNU one, this was completely useless for me on Linux.
> So I was thinking about replacing the CPU core with a different one.
> Initially I was thinking of the Starscream CPU core since that was
> quite popular in other emulators at that point in time. But that was
> also completely written in assembly, so it would have been harder to
> debug and not portable to other CPU architectures. Fortunately, I
> notice that the Amiga emulator UAE featured a good, cycle-accurate CPU
> core that was written in portable C code, so I decided to use that.