libwiiu example - Dual-screen rendering

void _start()
{
    /****************************>            Fix Stack            <****************************/
    //Load a good stack
    asm(
        "lis %r1, 0x1ab5 ;"
        "ori %r1, %r1, 0xd138 ;"
        );
    /****************************>           Get Handles           <****************************/
    //Get a handle to coreinit.rpl
    unsigned int coreinit_handle;
    OSDynLoad_Acquire("coreinit.rpl", &coreinit_handle);
    /****************************>       External Prototypes       <****************************/
    //OSScreen functions
    void(*OSScreenInit)();
    unsigned int(*OSScreenGetBufferSizeEx)(unsigned int bufferNum);
    unsigned int(*OSScreenSetBufferEx)(unsigned int bufferNum, void * addr);
    //OS Memory functions
    void*(*memset)(void * dest, uint32_t value, uint32_t bytes);
    void*(*OSAllocFromSystem)(uint32_t size, int align);
    void(*OSFreeToSystem)(void *ptr);
    //IM functions
    int(*IM_Open)();
    int(*IM_Close)(int fd);
    int(*IM_SetDeviceState)(int fd, void *mem, int state, int a, int b);
    /****************************>             Exports             <****************************/
    //OSScreen functions
    OSDynLoad_FindExport(coreinit_handle, 0, "OSScreenInit", &OSScreenInit);
    OSDynLoad_FindExport(coreinit_handle, 0, "OSScreenGetBufferSizeEx", &OSScreenGetBufferSizeEx);
    OSDynLoad_FindExport(coreinit_handle, 0, "OSScreenSetBufferEx", &OSScreenSetBufferEx);
    //OS Memory functions
    OSDynLoad_FindExport(coreinit_handle, 0, "memset", &memset);
    OSDynLoad_FindExport(coreinit_handle, 0, "OSAllocFromSystem", &OSAllocFromSystem);
    OSDynLoad_FindExport(coreinit_handle, 0, "OSFreeToSystem", &OSFreeToSystem);
    //IM functions
    OSDynLoad_FindExport(coreinit_handle, 0, "IM_Open", &IM_Open);
    OSDynLoad_FindExport(coreinit_handle, 0, "IM_Close", &IM_Close);
    OSDynLoad_FindExport(coreinit_handle, 0, "IM_SetDeviceState", &IM_SetDeviceState);
    /****************************>          Initial Setup          <****************************/
    //Restart system to get lib access
    int fd = IM_Open();
    void *mem = OSAllocFromSystem(0x100, 64);
    memset(mem, 0, 0x100);
    //set restart flag to force quit browser
    IM_SetDeviceState(fd, mem, 3, 0, 0);
    IM_Close(fd);
    OSFreeToSystem(mem);
    //wait a bit for browser end
    unsigned int t1 = 0x1FFFFFFF;
    while(t1--) ;
    //Call the Screen initilzation function.
    OSScreenInit();
    //Grab the buffer size for each screen (TV and gamepad)
    int buf0_size = OSScreenGetBufferSizeEx(0);
    int buf1_size = OSScreenGetBufferSizeEx(1);
    //Set the buffer area.
    OSScreenSetBufferEx(0, (void *)0xF4000000);
    OSScreenSetBufferEx(1, (void *)0xF4000000 + buf0_size);

    unsigned int(*OSScreenClearBufferEx)(unsigned int bufferNum, unsigned int temp);
    unsigned int(*OSScreenPutFontEx)(unsigned int bufferNum, unsigned int posX, unsigned int line, void * buffer);
    void(*DCFlushRange)(void *buffer, unsigned int length);
    unsigned int(*OSScreenFlipBuffersEx)(unsigned int bufferNum);
    unsigned int(*OSScreenPutPixelEx)(unsigned int buffer, unsigned int x, unsigned int y, unsigned int colour);

    OSDynLoad_FindExport(coreinit_handle, 0, "OSScreenClearBufferEx", &OSScreenClearBufferEx);
    OSDynLoad_FindExport(coreinit_handle, 0, "OSScreenPutFontEx", &OSScreenPutFontEx);
    OSDynLoad_FindExport(coreinit_handle, 0, "DCFlushRange", &DCFlushRange);
    OSDynLoad_FindExport(coreinit_handle, 0, "OSScreenFlipBuffersEx", &OSScreenFlipBuffersEx);
    OSDynLoad_FindExport(coreinit_handle, 0, "OSScreenPutPixelEx", &OSScreenPutPixelEx);

    //Clear both framebuffers.
    int ii = 0;
    for (ii; ii < 2; ii++)
    {
        OSScreenClearBufferEx(0, 0x000000FF); // Make sure that the TV screen's frame buffer is full of black (0x000000FF is equivalent to red=0, green=0, blue=0, alpha=255)
        DCFlushRange((void *)0xF4000000, buf0_size); // Flush the TV buffer's cache before finally...
        OSScreenFlipBuffersEx(0); // Rendering the changes to the TV screen only!

        OSScreenClearBufferEx(1, 0x000000FF); // Do the same for the GamePad screen. (above, the 0 represents buffer 0 - or the TV screen, the 1 here represents buffer 1 - the first GamePad)
        DCFlushRange((void *)0xF4000000 + buf0_size, buf1_size);
        OSScreenFlipBuffersEx(1);
    }

    int x = 0, y = 0; // Variables for drawing squares to the screen.

    /* Now, let's start our rendering! (to the TV screen, obviously) */
    OSScreenClearBufferEx(0, 0xFF0000FF); // Make the TV screen red (red=255, green=0, blue=0, alpha=255)
    for(x = 0; x < 50; x++) {
        for(y = 0; y < 50; y++) {
            OSScreenPutPixelEx(0, x, y, 0x0000FFFF); // Insert a blue pixel at the x and y coordinates (r=0 g=0 b=255 a=255)
        }
    }
    OSScreenPutFontEx(0, 3, 2, "This is the TV Screen."); // Write text to the TV
    DCFlushRange((void *)0xF4000000, buf0_size); // Flush the buffer cache
    OSScreenFlipBuffersEx(0); // Render changes

    /* Render to the GamePad screen, now. */
    OSScreenClearBufferEx(1, 0x00FF00FF); // Green background (you get the hang of hex colors eventually)
    for(x = 100; x < 150; x++) {
        for(y = 100; y < 150; y++) {
            OSScreenPutPixelEx(1, x, y, 0x0000FFFF);
        }
    }
    OSScreenPutFontEx(1, 5, 4, "This is the Wii U GamePad Screen.");
    DCFlushRange((void *)0xF4000000 + buf0_size, buf1_size);
    OSScreenFlipBuffersEx(1);

    /* Wait a few seconds before exiting... */
    t1 = 0xF0000000; // Approximately eight seconds (maybe?)
    while(t1--);

    for (ii; ii < 2; ii++)
    {
        OSScreenClearBufferEx(0, 0x000000FF); // Make sure that the TV screen's frame buffer is full of black (0x000000FF is equivalent to red=0, green=0, blue=0, alpha=255)
        DCFlushRange((void *)0xF4000000, buf0_size); // Flush the TV buffer's cache before finally...
        OSScreenFlipBuffersEx(0); // Rendering the changes to the TV screen only!

        OSScreenClearBufferEx(1, 0x000000FF); // Do the same for the GamePad screen. (above, the 0 represents buffer 0 - or the TV screen, the 1 here represents buffer 1 - the first GamePad)
        DCFlushRange((void *)0xF4000000 + buf0_size, buf1_size);
        OSScreenFlipBuffersEx(1);
    }
    _Exit(); // Return to HOME Menu
}