Posts Tagged - C

AmLogic s805x GXL SoC board bring up

One of the previous projects was related to bringing up our newly developed board with the AmLogic s805x SoC CPU board. I will describe how the proccess of bringing up looks like, what was tested and also we will take a look how the AmLogic board flashing proccess is carried out for GXL platform (G12B and more recent are very similar). This is our board:

Our developed Z8 board with AmLogic s805x SoC

The first stage of bringup is to build image for reference board. Our case is p241. We took a113 sources for this. Build p241 reference sources:

Build image

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# You need arm-linux-gnueabihf-gcc and aarch64-linux-gnu-gcc to be installed in system toolchains
$ sudo apt-get install zlib1g zlib1g-dev
$ source buildroot/build/setenv.sh
# Choose “mesongxl_p241_32_kernel49” // 37
$ ln -s aml-4.9 kernel/aml-3.14
$ ln -s aml-4.9 hardware/aml-3.14
$ make

After the proccess in complete everything will be at output/mesongxl_p241_32_kernel49/images with folowing parts:

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Crossplatform C++ Arch detection

You can simply get current arch usign following code, where on windows can be used GetNativeSystemInfo() and on macos and linux uname() function:

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std::string GetOSArch()
{
#ifdef CPK_OS_WIN
    SYSTEM_INFO info;
    GetNativeSystemInfo(&info);
    switch (info.wProcessorArchitecture) {
        case PROCESSOR_ARCHITECTURE_AMD64:
            return "x86_64";
        case PROCESSOR_ARCHITECTURE_INTEL:
            return "x86";
        case PROCESSOR_ARCHITECTURE_IA64:
            return "ia64";
    };
#endif
#if defined(CPK_OS_LINUX) || defined(CPK_OS_MACOS)
    long ret = -1;
    struct utsname u;

    if (ret == -1)
        ret = uname(&u);
    if (ret != -1) {
        if (strlen(u.machine) == 4 && u.machine[0] == 'i'
                && u.machine[2] == '8' && u.machine[3] == '6')
            return std::string("x86");
        if (strcmp(u.machine, "amd64") == 0) // Solaris
            return std::string("x86_64");

        return std::string(u.machine);
    }
#endif
    return "";
}

OS detection can be done for example on cmake side or with other definition like __WIN32:

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if(WIN32)
    add_definitions(-DCPK_OS_WIN)
else()
    if (${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
        add_definitions(-DCPK_OS_MACOS)
    else()
        add_definitions(-DCPK_OS_LINUX)
    endif()
endif()

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Missmatch of libstd++ library / _zst28__throw_bad_array_new_lengthv error

For example you install new compiler or MinGW C++ and you met error of _zst28__throw_bad_array_new_lengthv after compile time. You can verify you compiler with simple example:

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#include <iostream>
#include <vector>

using namespace std;
int main(void)
{
    vector <int> a = {2, 0, 1}; // problem line
    cout << "hellow world";
    return 0;
}

If you still get error on such simple example you have system libstd++ missmatch. Your system is taking this library from some other part of the system (NOT from compiler directory) of the %PATH% location. Edit you PATH variable and make compiler directory (for example: c:\mingw64\bin) to be ABOVE the problematic one. Or with other words: compiler directory must have more priority. Very popular problematic place is git - C:\Git\mingw64\bin, move it to the end of %PATH%.

The error must go away.

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Send Ctrl+C event to any Windows window

In some cases you want close the window on windows with ctrl+c combination, or invoke event for different reasons. On windows you can make such small program:

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#include <windows.h>
#include <stdio.h>

int main(int argc, char* argv[])
{
 int pid = atoi( argv[1] );
 printf("kill in console %d", pid);

 FreeConsole();
 if (AttachConsole(pid))
 {
     SetConsoleCtrlHandler(NULL, true);
     GenerateConsoleCtrlEvent(CTRL_C_EVENT, 0);
     FreeConsole();
     SetConsoleCtrlHandler(NULL, false);
 }


 return 0;
}

As argument you can pass a pid or the window proccess. (You can get it via system monitor).

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