dosbox breaks with MIPSpro, works with gcc - Printable Version

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dosbox breaks with MIPSpro, works with gcc - gijoe77 - 12-15-2018

very interesting problem with dosbox - compile it with gcc and it appears to work fine, compile it with MIPSpro and basically dosbox is unusable.  The "mount" command just either doesn't work or it crashes dosbox.  neko thread about it https://web.archive.org/web/20130210090939/http://forums.nekochan.net:80/viewtopic.php?t=10361

I thought it might be some sort of optimization bug with MIPSpro, but compiling with -O0 makes no difference.  

I've been toying around with the MOUNT class in src/dos/dos_programs.cpp and the DOS_Shell::Execute function in src/shell/shell_misc.cpp
but I was not able to find anything that stuck out to me (plus I suck at this) .

Anyone have any ideas how to troubleshoot the MIPSpro build?


Here is how I compiled dosbox 0.74-2 and got the source to be both gcc and MIPSpro happy:

btw one important point is the default keymapping is broken for IRIX, edit the autogenerated ~.dosbox/dosbox-0.74-2.conf file:

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RE: dosbox breaks with MIPSpro, works with gcc - gijoe77 - 03-15-2019

I've been digging a bit more into this, I'm putting "printf's" into places to see what's going on, and here is what I seem to think is going on.

It seems there is logic that checks if there are any strings/characters after the mount command, if not - just print what's currently mounted, otherwise do other stuff.  It seems no matter what I type after issuing the "mount" command, dosbox never see's any string of characters after the mount command.

for example here some code I've been focusing on - src/dos/dos_programs.cpp:



so no matter what I type in dosbox, be it
or
 (note this should trigger a showusage() function)
I've been trying to figure out how to troubleshoot/debug 


and


that are also in the dos_programs.cpp file but I'm having a hard time, if anyone has any ideas let me know!

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RE: dosbox breaks with MIPSpro, works with gcc - jpstewart - 03-16-2019

(03-15-2019, 02:10 AM)gijoe77 Wrote:  I've been digging a bit more into this, I'm putting "printf's" into places to see what's going on, and here is what I seem to think is going on.

It seems there is logic that checks if there are any strings/characters after the mount command, if not - just print what's currently mounted, otherwise do other stuff.  It seems no matter what I type after issuing the "mount" command, dosbox never see's any string of characters after the mount command.

That makes me wonder if there's a bug in the MIPSPro optimizer that's over-optimizing a function call right out of existence, thus returning a constant 0 instead of the actual number of arguments.  It looks like you've been compiling with -O2.  Have you tried lowering your optimization settings?

(03-15-2019, 02:10 AM)gijoe77 Wrote:  I've been trying to figure out how to troubleshoot/debug 

Code:

cmd->GetCount()

and

Code:

 cmd->FindString()

that are also in the dos_programs.cpp file but I'm having a hard time, if anyone has any ideas let me know!

While those functions are called from dos_programs.cpp, they're actually implemented in src/misc/setup.cpp, so you might try adding some printfs there for debugging.  It would be particularly interesting to see the value of cmds.size() in the GetCount function of setup.cpp.

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RE: dosbox breaks with MIPSpro, works with gcc - dexter1 - 03-17-2019

I got the same 'mount' command behaviour with my MIPSPro built binaries and the fact that dosbox runs fine from a gcc build and not a MIPSPro build led me to believe that there is a gcc-ism not taken into account when compiling with non-gcc compilers.

The gcc-ism __attribute__((packed)) appears to be a prime candidate which i have encountered before and can be substituted with #pragma pack(1) in the MIPSPro preprocessor.

So i've cobbled up a patch file like this:

This seems to work, although i have used it in combination with -signed in the CFLAGS/CXXFLAGS so i'm not completely sure which one did it. More testing needed tomorrow. It could be kind of ironic though that a preprocessor command meant for the Windows environment can help out our IRIX build :-)

But with this effort i have a working mount command in dosbox and successfully installed Wolfenstein3D. My challengeS didn't like the sound calls to ALmedia libraries, so i had to disable that in dosbox.conf. The game runs at a glacial speed from my R4400@175MHz over the network, so i'm sure it can do better on other machines.

The SDL i use is 1.2.15 with a modified configure script to enable the SDL_CDROM_DUMMY driver and disable SDL_CDROM_DISABLE which causes the dosbox exit with the CDROM init failure message. I'll post that later.

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RE: dosbox breaks with MIPSpro, works with gcc - gijoe77 - 03-20-2019

oh very cool dexter1!  This was actually the same issue that kept the mipspro build of prBoom-plus from working.

btw can you link your binary?  I'm still having some problems with my mipspro build and I would like to compare your working one.

BTW which version of dosbox did you patch?  The patchfile sort of failed for me so I went and patched the 0.74-2 files by hand.  FYI It looks like "packing" the "include/dos_inc.h" file fixes the "mount" issue.

The strange issue I had was if I used the "-g0" CFLAGS/CXXFLAGS, dosbox would hang if I typed "mount", but compiling with "-g" fixed the issue.

The main problem I'm having is I can run warcraft2 using the gcc build (sorry I only have warcraft2 to test currently), but when I try to launch it using the MIPSpro build I get

Here is my binary if you want to see how it fairs on your system (mips4)
https://www.mediafire.com/file/aaz5mj5v0ll5vn6/dosbox-0.74-2_cc_O3_ipa.xz/file

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RE: dosbox breaks with MIPSpro, works with gcc - dexter1 - 03-21-2019

Ah, you've made a build with the interprocedural optimizer, very nice. I'll test it tonight and will share my binary as well, but note that you also will have to substitute libSDL.so since i have made a fix which enables the dummy CDROM, so i'll send that as well.

If i'm generous i might even neko-package it and add it to my nekoware directory, so mips3 systems will reap the benefits of porting as well. I'll also distribute my patches to irisware.

The patch is indeed for 0.74-2 and i'm building with 6.5.22m and MPro 7.4.4, fully patched.

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RE: dosbox breaks with MIPSpro, works with gcc - gijoe77 - 03-21-2019

Here is the build env I used for the IPA optimized binary (I just noticed I built it using -g0, but it seems to be the only binary that didn't die on "mount" using -g0)...

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RE: dosbox breaks with MIPSpro, works with gcc - dexter1 - 04-14-2019

Thanks for your binary, Gijoe77

I had to build some extra libraries since your dosbox binary used some older nekoware libs. It's generally better to produce static builds so folks don't get stuck running the program.

Anyway, i found no real discernible difference in running your dosbox against mine. I usually run Wolfenstein 3D and Captain Comic.
I have made a nekoware build of all necessary SDL libraries and will uipload them to my nekoware directory the coming week. I'll also try to make a static build of my dosbox to share it with you

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RE: dosbox breaks with MIPSpro, works with gcc - gijoe77 - 04-14-2019

thanks dexter1

just wondering how do you compile things like this as static? I usually do "./configure --help" to see if there is a static option, other than that I don't really know...

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RE: dosbox breaks with MIPSpro, works with gcc - dexter1 - 06-16-2019

So "the coming week" actually took a bit longer than that, because i wanted to have both mips3 and mips4 static and dynamic build ready and a wish to design a nice Icon for the binary to go in 'Applications' Icon Catalog.

So i've placed the neko_dosbox tardist in my dual-mips3-mips4 nekoware directory. It is for both mips3 and mips4 and has two binaries: one dynamically linked with nekoware deps from the same directory and a semi-static one with only IRIX deps, so you don't have to go through the hassle with collecting all the nekoware deps.

A screenshot of DOSBox in action together with the icon:


The trick in making a semi-static binary is to relink with a command where only certain libraries have to be statically linked. This can be done win MIPSPro with -B static and -B dynamic. In the case of DOSBox it was:

As you can see, only the nekoware libraries are preceded by a -B static and the normal IRIX libraries preceded by -B dynamic

This information, as well as the patch file innards are in the neko_dosbox.opt.relnotes and neko_dosbox.opt.patches subsystems.
Let me know what you think of it.

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