Development on Pocket OS

To develop programs on pocket OS you need

• PocketOSdev.zip archive
• Visual C++ 6 or Visual Studio Express (Exemples tested with Visual Studio Express 9 (free to download))

First unpack the PocketOSdev.zip archive in a Windows directory (ex: C:\PosApp)

The archive content is:

• <DIR> Include            C compiler headers
• <DIR> Lib                  C compiler libraries
• <DIR> Hellow            Simple hello world (+ display command line arguments)
• <DIR> CurveDraw     Simple graphic demo
• <DIR> CurveAnim      Simple graphic animation demo
• <DIR> Memspeed      Bench memory transfer speed (not really usefull)
• <DIR> Tcc                 Tcc compiler sources for Pocket OS
• <DIR> Qemu              Qemu emulator, used to test a program
• <DIR> Windrv            Disk image for emulators.
  • Mounted as C: with Windows or qemu emulator.
  • Executable compiled in release mode are copied into the root of this disc. (Can be changed in the project options in Visual Studio). Attention, qemu mounts the directory image in read only.
• mkprj.exe                   Command line program used to create a Visual Studio (6 and Express) project for Pocket OS. (and set all required link options)
  • Syntax: mkprj projectname
    • Created the directory and file projectname. Dsp and. Dsw (VC6) and. vcproj (VS Express) + main.c
  • Two configurations are defined:
    • Debug: allows you to debug a program using visual Windows emulator (POSemu.exe)
    • Release: generates an executable for pocket OS, it can be tested with qemu or on a real PC . The executable is copied on the root of windrv in order to be tested by the emulator.
• runqemu.bat:                Batch file used to launch qemu. The drive 'windrv' is mounted as drive C: (in read only mode). Used to test an executable compiled in release
• POSemu.exe               Executable of Pocket OS emulator for Windows.

To start:

Start Visual Studio.

• Open a project in an example directory (use .vcproj for express, do not load .dsw)
• Select build configuration (default is debug)
• In Debug
  • Build project
  • Run Project. It start the windows emulator automatically and you can trace/debug program
• In Release
  • Build project. The executable is copied on root of windrv (emulator disk image)
  • Start an emulator (qEmu or POSemu.exe), and launch the program using command line.

To test on real PC, just copy the executable on the flash key, reboot the PC with Pocket OS and launch it using command line.

To create a new project:

• Open Windows console
• Move to the Pocket OS dev directory you have created.
  • ex: cd C:\PosApp
• Create project using mkprj.exe command line tool
  • ex: mkprj myproj. This will create myproj directory, containing:
    • myproj.vcproj (visual express project file)
    • myproj.dsp (visual c++ 6 project file. Can be deleted if unused)
    • myproj.dsw (visual c++ 6 project file. Can be deleted if unused)
    • main.c (simple main doing nothing, just include "pos.h" header and debug function that is required to link in debug)
• Open the project with Visual Studio. You can then build/debug as described in examples.
• Note: The project must be created in dev directory (here C:\PosApp) because generated project files refer to paths relative to this directory. So it will not work if you create a project somewhere else (unless you modify path in project configuration)

Notes:

• It is convenient to create a shortcut to runqemu.bat and POSemu.exe in Windows task bar.
• In the qemu emulator, the hard drive is mounted as read only, so an application cannot write to it. To test an application that makes disk writes, it is possible to create a volume 'ramdisk' with commands:
  • ramdrive R: 16 (creates a ramdisk of 16MB named R: (can be changed))
  • If the content of C: is small, you can copy all the content to R: using:
    • xcopy C:\* R: (copy all the contents into the ramdrive)
    • path = R:\bin;R:\tcc (change path to R:)
  • You can add these command to autoexec.sh to avoid typing them at each time.
• Programming in C++. Currently the programming in C++ is not expected, however it is possible but with restrictions:
  • Classes must not use Constructors/Destructors (can use explicitly called init functions)
  • The new/delete must be replaced by some malloc/free
  • Try/Catch not supported (but you can use setjmp / longjump)
• Under POS, it is possible to compile examples with integrated compilator TCC, you can use the script 'build.sh' contained in each example directory (type command 'sh build.sh'.) (Remember, the disk on qemu emulator is read only, but it writable on Windows emulator)
  • TCC library (libpostcc.a) is currently very small, it allows just TCC to rebuild itself.
  • It is possible to 'recover' the mingw32 libraries, but they need to be converted to ELF32.
    • Extract objects (.o) from mingw library using 'ar':
      • ar x libxxx.x
    • Convert the objects to ELF32-i386 format using objcopy:
      • objcopy -O xxx.o ELF32-i386 - remove-leading-char
    • Create the new TCC library with converted objects
      •  ar rcs obj1.o obj2.o ... libnew.a
    • Be careful not to include functions specific to Windows kernel (eg malloc, printf, etc ...)