Tutorial : How Compile Dosbox.

Fresh_meat · Post by **Fresh_meat** » Thu Apr 27, 2006 09:43 pm

You want get the better of your Dosbox ? You can try it.

What you need to get :

- Dosbox sources (or other)
- tar utility
- gunzip utility
- the latest version of gcc
- make utility or an IDE who can compilling with gcc
- a shell
- a text editor

What you need to know :

- the specifications of your CPU
- what is your gcc version
- if you have a 32 or a native 64 bits operating system

Before starting :

- gcc 3.x.x don't have the ssa optimisation unit so if you use that version, don't add the flag

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-fssa

- Apple power G4 and all cpu based on the same core don't support the third low-level optimisation level so if you have that kind of chip don't use the flag

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-O3

but

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-O2

- when I say for example "pentium4" it's also for all chip of this familly like celeron, pentium and xeon
- if you use an IDE, you must settle the optimisations in your IDE
- all of this optimisations are theoretically safe but you can try other by yourself
- the pipe flag is just to speed up the compilation
- the CHOST flag is specific to your operating system, take a look to the gcc man page
- if you don't have a 64 bit operating system, you need to use the 32 bits flags

* First you need to unpack the sources with gunzip, tar and you shell

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tar -xvzpf dosbox-0.65.tar.gz

* Now, go into the new directory

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cd dosbox-0.65

* If you use an IDE you need to creat a project, load all files and settle all your options, and make your project

* If you work with a shell you need to export 3 flags, see at the end to the specifications

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export CHOST="my flag"
export CFLAGS="my flag"
export CXXFLAGS="my flag"

* You must generate the makefile

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./configure

* Now take a look to the makefile and see if the flags are good, if there aren't, you must modify them with you text editor

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cat Makefile
emacs Makefile

#### Now the flags

of cause you need adjust the CHOST

- Pentium III

CHOST="i686-pc-linux-gnu"
CFLAGS="-march=pentium3 -O3 -pipe -fomit-frame-pointer -fmerge-all-constants -ffast-math -funswitch-loops -mmmx -msse -fssa"
CXXFLAGS="${CFLAGS}"

- Mobile Pentium III

CHOST="i686-pc-linux-gnu"
CFLAGS="-march=pentium3m -O3 -pipe -fomit-frame-pointer -fmerge-all-constants -ffast-math -funswitch-loops -mmmx -msse -fssa"
CXXFLAGS="${CFLAGS}"

- Pentium IV

CHOST="i686-pc-linux-gnu"
CFLAGS="-march=pentium4 -O3 -pipe -fomit-frame-pointer -fmerge-all-constants -ffast-math -funswitch-loops -mmmx -msse -msse2 -fssa"
CXXFLAGS="${CFLAGS}"

- Mobile Pentium IV

CHOST="i686-pc-linux-gnu"
CFLAGS="-march=pentium4m -O3 -pipe -fomit-frame-pointer -fmerge-all-constants -ffast-math -funswitch-loops -mmmx -msse -msse2 -fssa"
CXXFLAGS="${CFLAGS}"

- Pentium IV with 32 bits Presscot core

CHOST="i686-pc-linux-gnu"
CFLAGS="-march=pentium4m -O3 -pipe -fomit-frame-pointer -fmerge-all-constants -ffast-math -funswitch-loops -mmmx -msse -msse2 -msse3 -fssa"
CXXFLAGS="${CFLAGS}"

- Pentium IV with 32 bits Prescott core

CHOST="i686-pc-linux-gnu"
CFLAGS="-march=prescott -O3 -pipe -fomit-frame-pointer -fmerge-all-constants -ffast-math -funswitch-loops -mmmx -msse -msse2 -msse3 -fssa"
CXXFLAGS="${CFLAGS}"

- Athlon

CHOST="i686-pc-linux-gnu"
CFLAGS="-march=athlon -O3 -pipe -fomit-frame-pointer -fmerge-all-constants -ffast-math -funswitch-loops -mmmx -m3dnow -fssa"
CXXFLAGS="${CFLAGS}"

- Athlon-tbird

CHOST="i686-pc-linux-gnu"
CFLAGS="-march=athlon-tbird -O3 -pipe -fomit-frame-pointer -fmerge-all-constants -ffast-math -funswitch-loops -mmmx -m3dnow -fssa"
CXXFLAGS="${CFLAGS}"

- Athlon 4

CHOST="i686-pc-linux-gnu"
CFLAGS="-march=athlon-4 -O3 -pipe -fomit-frame-pointer -fmerge-all-constants -ffast-math -funswitch-loops -mmmx -m3dnow -msse -fssa"
CXXFLAGS="${CFLAGS}"

- Athlon XP

CHOST="i686-pc-linux-gnu"
CFLAGS="-march=athlon-xp -O3 -pipe -fomit-frame-pointer -fmerge-all-constants -ffast-math -funswitch-loops -mmmx -m3dnow -msse -fssa"
CXXFLAGS="${CFLAGS}"

- Athlon MP

CHOST="i686-pc-linux-gnu"
CFLAGS="-march=athlon-mp -O3 -pipe -fomit-frame-pointer -fmerge-all-constants -ffast-math -funswitch-loops -mmmx -m3dnow -msse -fssa"
CXXFLAGS="${CFLAGS}"

- Pentium IV with 64 bits Prescott core

CHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=nocona -O3 -pipe -fomit-frame-pointer -fmerge-all-constants -ffast-math -funswitch-loops -mmmx -msse -msse2 -msse3 -fssa"
CXXFLAGS="${CFLAGS}"

- Opteron

CHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=opteron -O3 -pipe -fomit-frame-pointer -fmerge-all-constants -ffast-math -funswitch-loops -mmmx -m3dnow -msse -msse2 -msse3 -fssa"
CXXFLAGS="${CFLAGS}"

- Athlon 64

CHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=athlon64 -O3 -pipe -fomit-frame-pointer -fmerge-all-constants -ffast-math -funswitch-loops -mmmx -m3dnow -msse -msse2 -msse3 -fssa"
CXXFLAGS="${CFLAGS}"

- Athlon FX

CHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=athlon-fx -O3 -pipe -fomit-frame-pointer -fmerge-all-constants -ffast-math -funswitch-loops -mmmx -m3dnow -msse -msse2 -msse3 -fssa"
CXXFLAGS="${CFLAGS}"

- G4 7400

CHOST="powerpc-unknown-linux-gnu"
CFLAGS="-mcpu=7400 -O2 -pipe -fsigned-char -maltivec
-mabi=altivec -mpowerpc-gfxopt"
CXXFLAGS="${CFLAGS}"

- G4 7450

CHOST="powerpc-unknown-linux-gnu"
CFLAGS="-mcpu=7450 -O2 -pipe -fsigned-char -maltivec
-mabi=altivec -mpowerpc-gfxopt"
CXXFLAGS="${CFLAGS}"

- G5

CHOST="powerpc64-unknown-linux-gnu"
CFLAGS="-mcpu=G5 -O3 -pipe -fsigned-char -maltivec
-mabi=altivec -mpowerpc-gfxopt"
CXXFLAGS="${CFLAGS}"

Thanks for your comments, remarks ...

Post by **DustyStyx** » Thu Apr 27, 2006 11:52 pm

Thank you! This is verry informative, you get a sticky!

Fresh_meat · Post by **Fresh_meat** » Fri Apr 28, 2006 08:22 am

Thanks, of cause you can compil all other softwares like that ... Darkplaces for example.

Jethro · Post by **Jethro** » Fri May 05, 2006 01:58 pm

Damn, I've tried to follow your tips but... I've got executable that is much slower thn original one :/ I was using mingw+msys with P4 Prescott optimalisation with no luck. I've seen that CheapAlert was running Blood by setting core to dynamic and cycles to 40k, but my machine is unable to handle that much and I get 5-10 fps. Also, I was wondering about this CHOST settings: I've used i686-pc-windows-gnu, but ./configure detects "i686-pc-mingw32", so I was wondering if it was better to leave autodetected value instead of setting my own one.
So, anyone knows how to:

a) set up compiler to get faster exec/what could have I done wrong?
b) how to set up dosbox to get satisfying framerate?

Fresh_meat · Post by **Fresh_meat** » Fri May 05, 2006 07:47 pm

a) set up compiler to get faster exec/what could have I done wrong?

I run dosbox on Gentoo Linux only so I don't know if you have settleed the good chost but I think you must use "i686-pc-mingw32"

b) how to set up dosbox to get satisfying framerate?

You need to find your own settle, it's very specific. For example, I have a P4C 3.0GHz under gentoo, first I settle "memory size" to 128, "core" to dynamic, cpu cycle to 25000, and 1 frameskipe, it's the best settle for my config, under and over I have a bad result.
Somethong else : Cryptic passage is very slow, so don't worry about it