DOSBox-X branch

Here you can discuss the development of patches.

Re: DOSBox-X branch

Postby TheGreatCodeholio » 2019-1-18 @ 04:17

hail-to-the-ryzen wrote:Is PIT mode 3 used by any PC games or past demos? I recall there was discussion on your github site about its use in the PC-98, and that mode=3 is also available on the PC (accurate emulation).


If you want to know exactly what the 8254 can do, look at the Intel datasheet.
DOSBox-X project: more emulation better accuracy.
DOSLIB and DOSLIB2: Learn how to tinker and hack hardware and software from DOS.
User avatar
TheGreatCodeholio
Oldbie
 
Posts: 694
Joined: 2011-8-18 @ 20:15
Location: Seattle, WA

Re: DOSBox-X branch

Postby TheGreatCodeholio » 2019-1-18 @ 04:18

I have an issue open with a dump of ideas for test programs to write in DOSLIB that play with the 8254 and it's functions. Some have been written already.
DOSBox-X project: more emulation better accuracy.
DOSLIB and DOSLIB2: Learn how to tinker and hack hardware and software from DOS.
User avatar
TheGreatCodeholio
Oldbie
 
Posts: 694
Joined: 2011-8-18 @ 20:15
Location: Seattle, WA

Re: DOSBox-X branch

Postby hail-to-the-ryzen » 2019-1-18 @ 07:37

Thank you for the detailed reply and for the doslib test programs. I will look at the datasheet carefully since I was trying to understand by merely reading the code differences. Now I recall that there was a dosbox-x issue open with Corncob 3d, I think it must have been tested in VGA code running in EGA mode, and whether the timer code changes will address that issue or others.
hail-to-the-ryzen
Member
 
Posts: 340
Joined: 2017-3-09 @ 01:34

Re: DOSBox-X branch

Postby TheGreatCodeholio » 2019-1-18 @ 08:03

Corncob 3D requires VGA even though the main game uses EGA graphics mode.

I just found that I can eliminate the on-screen flickering by adding video memory delay. Apparently if your video memory is too fast Corncob 3D will flicker badly.
DOSBox-X project: more emulation better accuracy.
DOSLIB and DOSLIB2: Learn how to tinker and hack hardware and software from DOS.
User avatar
TheGreatCodeholio
Oldbie
 
Posts: 694
Joined: 2011-8-18 @ 20:15
Location: Seattle, WA

Re: DOSBox-X branch

Postby hail-to-the-ryzen » 2019-1-18 @ 08:13

That is great. I think Perfect General does the same in ega mode - I will try to test your fix there.
hail-to-the-ryzen
Member
 
Posts: 340
Joined: 2017-3-09 @ 01:34

Re: DOSBox-X branch

Postby TheGreatCodeholio » 2019-1-18 @ 08:16

hail-to-the-ryzen wrote:That is great. I think Perfect General does the same in ega mode - I will try to test your fix there.


Excellent. For DOSBox-X try vmemdelay=1000
DOSBox-X project: more emulation better accuracy.
DOSLIB and DOSLIB2: Learn how to tinker and hack hardware and software from DOS.
User avatar
TheGreatCodeholio
Oldbie
 
Posts: 694
Joined: 2011-8-18 @ 20:15
Location: Seattle, WA

Re: DOSBox-X branch

Postby hail-to-the-ryzen » 2019-1-18 @ 08:27

The title screen also does not gradually appear in svn code, that suggestion should help there, too.
hail-to-the-ryzen
Member
 
Posts: 340
Joined: 2017-3-09 @ 01:34

Re: DOSBox-X branch

Postby hail-to-the-ryzen » 2019-1-19 @ 02:21

Confirmed that the vmemdelay of around 1000 is sufficient. It's also possible to cause the same issue and solve it in pcem by modifying its isa timing function. The issue led me to debug some issues in a dos source port of doom, and if you are interested in testing it with your latest code base, I can upload it.
hail-to-the-ryzen
Member
 
Posts: 340
Joined: 2017-3-09 @ 01:34

Re: DOSBox-X branch

Postby hail-to-the-ryzen » 2019-2-01 @ 00:54

Was the Explora demo tested with 0.74 or built with fpu interpreter core? All cores show the rendering issue? And the video mode is the same in all tests? Was -x built with 32 and 64 bit?
hail-to-the-ryzen
Member
 
Posts: 340
Joined: 2017-3-09 @ 01:34

Re: DOSBox-X branch

Postby TheGreatCodeholio » 2019-2-01 @ 03:21

hail-to-the-ryzen wrote:Was the Explora demo tested with 0.74 or built with fpu interpreter core? All cores show the rendering issue? And the video mode is the same in all tests? Was -x built with 32 and 64 bit?


I got the same result using either normal or dynamic core. I generally do not test the full and simple cores.

The demo appears to use one specific video mode.
DOSBox-X project: more emulation better accuracy.
DOSLIB and DOSLIB2: Learn how to tinker and hack hardware and software from DOS.
User avatar
TheGreatCodeholio
Oldbie
 
Posts: 694
Joined: 2011-8-18 @ 20:15
Location: Seattle, WA

Re: DOSBox-X branch

Postby hail-to-the-ryzen » 2019-2-01 @ 07:16

I should check, but that means DOSBox SVN compiles with both types of fpu emulation (x86 specific and the interpreter type).

Edit (from fpu.cpp):
Code: Select all
#if C_FPU_X86
#include "fpu_instructions_x86.h"
#else
#include "fpu_instructions.h"
#endif
hail-to-the-ryzen
Member
 
Posts: 340
Joined: 2017-3-09 @ 01:34

Re: DOSBox-X branch

Postby TheGreatCodeholio » 2019-2-01 @ 07:20

DOSBox-X eliminated the fpu_instructions_x86.h file.

I compiled DOSBox SVN with and without C_FPU_X86 and it didn't make any difference.

The fault is somewhere else.
DOSBox-X project: more emulation better accuracy.
DOSLIB and DOSLIB2: Learn how to tinker and hack hardware and software from DOS.
User avatar
TheGreatCodeholio
Oldbie
 
Posts: 694
Joined: 2011-8-18 @ 20:15
Location: Seattle, WA

Re: DOSBox-X branch

Postby hail-to-the-ryzen » 2019-2-01 @ 07:21

I reproduced the issue in a 32-bit custom build, but much of the video emulation in the build is like SVN.

Edit: did you test with early versions of dosbox-x?
hail-to-the-ryzen
Member
 
Posts: 340
Joined: 2017-3-09 @ 01:34

Re: DOSBox-X branch

Postby TheGreatCodeholio » 2019-2-01 @ 07:24

hail-to-the-ryzen wrote:I reproduced the issue in a 32-bit custom build, but much of the video emulation in the build is like SVN.

Edit: did you test with early versions of dosbox-x?


I used the magic of git checkout to go back pretty far. It seems like the bug, whatever it is, has been there for a long time.
DOSBox-X project: more emulation better accuracy.
DOSLIB and DOSLIB2: Learn how to tinker and hack hardware and software from DOS.
User avatar
TheGreatCodeholio
Oldbie
 
Posts: 694
Joined: 2011-8-18 @ 20:15
Location: Seattle, WA

Re: DOSBox-X branch

Postby hail-to-the-ryzen » 2019-2-01 @ 07:26

Thanks, I'll test further.
hail-to-the-ryzen
Member
 
Posts: 340
Joined: 2017-3-09 @ 01:34

Re: DOSBox-X branch

Postby hail-to-the-ryzen » 2019-2-01 @ 07:37

I can reproduce with the normal core (DOSBox-X like), but it doesn't show the artifacts with core=full nor with a SVN like dynamic core.
hail-to-the-ryzen
Member
 
Posts: 340
Joined: 2017-3-09 @ 01:34

Re: DOSBox-X branch

Postby TheGreatCodeholio » 2019-2-01 @ 07:54

hail-to-the-ryzen wrote:I can reproduce with the normal core (DOSBox-X like), but it doesn't show the artifacts with core=full nor with a SVN like dynamic core.


Odd, on x86_64 Linux I see the artifacts no matter what core I select. Hm..
DOSBox-X project: more emulation better accuracy.
DOSLIB and DOSLIB2: Learn how to tinker and hack hardware and software from DOS.
User avatar
TheGreatCodeholio
Oldbie
 
Posts: 694
Joined: 2011-8-18 @ 20:15
Location: Seattle, WA

Re: DOSBox-X branch

Postby hail-to-the-ryzen » 2019-2-01 @ 07:55

It also occurs in PCem, at least in a custom build of it. It has the issue but more of it and it freezes after a few seconds or less of the artifacts.
hail-to-the-ryzen
Member
 
Posts: 340
Joined: 2017-3-09 @ 01:34

Re: DOSBox-X branch

Postby hail-to-the-ryzen » 2019-2-02 @ 02:47

hail-to-the-ryzen wrote:I should check, but that means DOSBox SVN compiles with both types of fpu emulation (x86 specific and the interpreter type).

Edit (from fpu.cpp):
Code: Select all
#if C_FPU_X86
#include "fpu_instructions_x86.h"
#else
#include "fpu_instructions.h"
#endif

Confirmed that building SVN with the non-x86 fpu emulation leads to the rendering artifacts in the demo EXPLORA. Built with O2 optimization. So, SVN has the same issue as DOSBox-X.

Disabled the x86 fpu emulation with this command:
Code: Select all
./configure --disable-fpu-x86
hail-to-the-ryzen
Member
 
Posts: 340
Joined: 2017-3-09 @ 01:34

Re: DOSBox-X branch

Postby TheGreatCodeholio » 2019-2-02 @ 04:13

Mind if I borrow the x86 FPU header from SVN?
DOSBox-X project: more emulation better accuracy.
DOSLIB and DOSLIB2: Learn how to tinker and hack hardware and software from DOS.
User avatar
TheGreatCodeholio
Oldbie
 
Posts: 694
Joined: 2011-8-18 @ 20:15
Location: Seattle, WA

PreviousNext

Return to DOSBox Patches

Who is online

Users browsing this forum: No registered users and 1 guest