Difference between revisions of "HOWTO-Debug-Endian-Issues"

Once you've downloaded and extracted the VM archive, you'll need to install QEMU for your system with your usual package manager (Windows builds are available [https://qemu.weilnetz.de/w64/ here]).

Once you've downloaded and extracted the VM archive, you'll need to install QEMU for your system with your usual package manager (Windows builds are available [https://qemu.weilnetz.de/w64/ here]).

Then, create one of the following scripts in the same directory as the VM image.

Then, create one of the following scripts in the same directory as the VM image.

* <code>-g 1024x750x32</code>: VM screen resolution and bit depth. You can try suiting it to your needs, but strange results may happen with some resolutions, and, since there's no graphics acceleration, making the window too big may worsen performance. Reducing the bit-depth from <code>32</code> to <code>24</code> bits could help in some cases.

* <code>-g 1024x750x32</code>: VM screen resolution and bit depth. You can try suiting it to your needs, but strange results may happen with some resolutions, and, since there's no graphics acceleration, making the window too big may worsen performance. Reducing the bit-depth from <code>32</code> to <code>24</code> bits could help in some cases.

* <code>-cdrom /path/to/host/game.iso</code>: this is a quick way of sharing some game or development files from your host to the VM (it will then appear in its file manager). Other file-sharing options between the two systems are possible ([[#Various options for a more convenient setup|see below]]).

* <code>-cdrom /path/to/host/game.iso</code>: this is a quick way of sharing some game or development files from your host to the VM (it will then appear in its file manager). Other file-sharing options between the two systems are possible ([[#Various options for a more convenient setup|see below]]).

Then, run that script. A QEMU window should appear, and a Linux system should boot. Wait until a full [https://docs.xfce.org/4.10/start XFCE desktop] appears (this may take a couple of minutes, depending on your host system performance).

Then, run that script. A QEMU window should appear, and a Linux system should boot. Wait until a full [https://docs.xfce.org/4.10/start XFCE desktop] appears (this may take a couple of minutes, depending on your host system performance).

Keyboard layout can be changed in Applications Menu > Settings > Keyboard > Layout, or with <code>setxkbmap</code> (see also https://wiki.debian.org/Keyboard), if necessary. Default credentials are <code>scummvm</code> / <code>scummvm</code>, since this is just a local development environment.

Keyboard layout can be changed in Applications Menu > Settings > Keyboard > Layout, or with <code>setxkbmap</code> (see also https://wiki.debian.org/Keyboard), if necessary. Default credentials are <code>scummvm</code> / <code>scummvm</code>, since this is just a local development environment.

Don't expect the included web browser to be remotely useful for anything.

Don't expect the included web browser to be remotely useful for anything.

For development purposes, you may want to install the following set of tools, if you use them:

For development purposes, you may want to install the following set of tools, if you use them:

Compilers, GNU Make, GDB, Git and SDL development files are already installed in this image. The APT package manager is also pre-configured to use the older [https://www.debian.org/distrib/archive.en.html Debian 8 archive] files. Some Debian 8 GPG keys have expired since then, though, so APT will print some security warnings.

Compilers, GNU Make, GDB, Git and SDL development files are already installed in this image. The APT package manager is also pre-configured to use the older [https://www.debian.org/distrib/archive.en.html Debian 8 archive] files. Some Debian 8 GPG keys have expired since then, though, so APT will print some security warnings.

Cloning the repository and compiling ScummVM is done through the [[Compiling_ScummVM/GCC|usual means]], with some important points:

Cloning the repository and compiling ScummVM is done through the [[Compiling_ScummVM/GCC|usual means]], with some important points:

* Some tools such as Valgrind become unbearably slow when emulated. <code>--enable-asan</code> is available, but its implementation is from 2015.

* Some tools such as Valgrind become unbearably slow when emulated. <code>--enable-asan</code> is available, but its implementation is from 2015.

* The older 1.2 branch of SDL is used, since rendering is done through an unaccelerated framebuffer at the moment, and SDL1.2 is a better option than SDL2 for this case.

* The older 1.2 branch of SDL is used, since rendering is done through an unaccelerated framebuffer at the moment, and SDL1.2 is a better option than SDL2 for this case.

You can then run the resulting <code>scummvm</code> binary, while making sure that some ScummVM options such as Global Options > Paths > Extra Path are properly configured for development. Then, add your game, and see how it behaves on big-endian! Run <code>gdb</code> on it if necessary, make the appropriate code changes, and iterate with <code>make</code> until it works as expected.

You can then run the resulting <code>scummvm</code> binary, while making sure that some ScummVM options such as Global Options > Paths > Extra Path are properly configured for development. Then, add your game, and see how it behaves on big-endian! Run <code>gdb</code> on it if necessary, make the appropriate code changes, and iterate with <code>make</code> until it works as expected.

=== Various options for a more convenient setup ===

=== Various options for a more convenient setup ===

If you need a powerful and user-friendly IDE inside the VM, you won't have many options, because this is an old and limited Linux system. If you don't like console text editors, you're probably out of luck (unless you want to try <code>sudo apt-get install codeblocks</code>). One option could be to work from your usual IDE on your regular desktop, and share its files with the VM.

If you need a powerful and user-friendly IDE inside the VM, you won't have many options, because this is an old and limited Linux system. If you don't like console text editors, you're probably out of luck (unless you want to try <code>sudo apt-get install codeblocks</code>). One option could be to work from your usual IDE on your regular desktop, and share its files with the VM.

The VM can access its host system via the <code>10.0.2.2</code> IP address (useful if you want to share files from the host to the VM with an NFS, SMB, HTTP, or FTP server).

The VM can access its host system via the <code>10.0.2.2</code> IP address (useful if you want to share files from the host to the VM with an NFS, SMB, HTTP, or FTP server).

[https://wiki.archlinux.org/title/QEMU#VNC Connecting through VNC] is also possible, but it's probably not going to be a great experience.

[https://wiki.archlinux.org/title/QEMU#VNC Connecting through VNC] is also possible, but it's probably not going to be a great experience.

If you need a bit more storage space inside the VM, some big and unnecessary tools can be removed:

If you need a bit more storage space inside the VM, some big and unnecessary tools can be removed: