[hatari-devel] Mahabharata demo problem ?

[Laurent Sallafranque]

I've given a try to the patch.

No regression found.
Is it me, or is the screen between to screens in a demo are better with 
the patch ?
(I mean, between each demo screen, when resolution of screen size 
change, it always took a little time (but visible and now, it seems to 
have disapeared).

For Videl, shouldn't horizontal size be read in
     $FF8288 (word) : HDB - Horizontal Display Begin
     $FF828A (word) : HDE - Horizontal Display End

instead of     $FF8210 (word) : VWRAP - line width ?

For vertical size, we read
     $FF82A8 (word) : VDB - Vertical Display Begin
     $FF82AA (word) : VDE - Vertical Display End


I had compiled all the videl registers for when I would work on it.
Here it is, perhaps it could be included as comment at top of the videl 
file ?

/*
   It can run at 2 frequencies : 25 Mhz or 32 MHz

   Hardware I/O registers:
     $FF8006 (byte) : monitor type
     $FF820E (word) : offset to next line
     $FF8210 (word) : VWRAP - line width
     $FF8260 (byte) : ST shift mode
     $FF8265 (byte) : Horizontal scroll register
     $FF8266 (word) : Falcon shift mode
     $FF8280 (word) : HHC - Horizontal Hold Counter
     $FF8282 (word) : HHT - Horizontal Hold Timer
     $FF8284 (word) : HBB - Horizontal Border Begin
     $FF8286 (word) : HBE - Horizontal Border End
     $FF8288 (word) : HDB - Horizontal Display Begin
     $FF828A (word) : HDE - Horizontal Display End
     $FF828C (word) : HSS - Horizontal SS
     $FF828E (word) : HFS - Horizontal FS
     $FF8290 (word) : HEE - Horizontal EE
     $FF82A0 (word) : VFC - Vertical Frequency Counter
     $FF82A2 (word) : VFT - Vertical Frequency Timer
     $FF82A4 (word) : VBB - Vertical Border Begin
     $FF82A6 (word) : VBE - Vertical Border End
     $FF82A8 (word) : VDB - Vertical Display Begin
     $FF82AA (word) : VDE - Vertical Display End
     $FF82AC (word) : VSS - Vertical SS
     $FF82C0 (word) : VCO - Video control
     $FF82C2 (word) : VMD - Video mode
*/

Regards

Laurent



Le 15/01/2011 21:30, Eero Tamminen a écrit :
> Hi,
>
> On lauantai 15 tammikuu 2011, Eero Tamminen wrote:
>> Not unbounded sizes.  During the demo, 5120x200 and 5120x240
>> sized resolutions are requested several times.
>>
>> I think there could be some corner-case that Hatari Videl code isn't
>> emulating.   Maybe the real HW clips large resolutions and like ST/STE
>> does something "unexpected" when being requested funny resolution
>> changes.
> Videl code does following:
>
> get width (register is scanline size in words):
>          (handleReadW(HW + 0x10)&  0x03ff) * 16 / VIDEL_getScreenBpp();
>
> get bpp:
> ---------------------
>          int f_shift = handleReadW(HW + 0x66);
>          int st_shift = handleRead(HW + 0x60);
>          /* to get bpp, we must examine f_shift and st_shift.
>           * f_shift is valid if any of bits no. 10, 8 or 4
>           * is set. Priority in f_shift is: 10 ">" 8">" 4, i.e.
>           * if bit 10 set then bit 8 and bit 4 don't care...
> 	...
>          if (f_shift&  0x400)            /* Falcon: 2 colors */
>                  bits_per_pixel = 1;
>          else if (f_shift&  0x100)       /* Falcon: hicolor */
>                  bits_per_pixel = 16;
> ---------------------
>
> If scanline register value is 320, and bpp gets set to 1 instead of 16:
> ->  width = 5120
>
> And indeed when I traced changes in all of these registers:
> b (0xff8210).w ! (0xff8210).w :trace
> b (0xff8266).w ! (0xff8266).w :trace
> b (0xff8260).b ! (0xff8260).b :trace
>
> Whenever the window goes too wide, I see:
>    $ff8266 = $400
> 2. CPU breakpoint condition(s) matched 1 times.
> WARNING: too large screen size 5120x240 ->  divided by 4x1!
>    $ff8266 = $100
>
> I.e. Falcon shifter control register 2-color mode bit is toggled, but
> nothing else.
>
>
> I remember that monochrome toggling on color resolutions did something
> special on ST(e), maybe something similar should happen on Falcon's Videl?
>
>
> There's also this suspicious stuff in VIDEL_renderScreen():
>          if (since_last_change>  2) {
>                  if (vw>  0&&  vw != width) {
>                          Dprintf(("CH width %d\n", width));
>                          width = vw;
>                          since_last_change = 0;
> ...
>         if (since_last_change == 3) {
>                  HostScreen_setWindowSize(width, height, bpp == 16 ? 16 : ...
>          }
>          if (since_last_change<  4) {
>                  since_last_change++;
>                  return false;
>          }
>
> This function is called from Video_DrawScreen() which is called from
> Video_InterruptHandler_VBL() and on fullscreen switches.
>
> ->  The resolution is changed 3 VBLs later than it actually happens and
>       rendering of Falcon screen content to the Hatari window is skipped
>       during this time.
>
> Everything seems to work fine if I remove that (see the attached patch).
>
> Thomas?
>
>
> 	- Eero
>
>
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