Visual C++ Runtime

Since you can't link standard C++ runtime to your kernel, you'll need several functions to replace it's functionality. This article provides information on how to implement your own C++ runtime for Visual C++ compiler.

Call Constructors For Global Static Variables

This code will help to call all constructors for global static variables.

// Constructor prototypes
typedef void (__cdecl *_PVFV)(void);
typedef int  (__cdecl *_PIFV)(void);

// Linker puts constructors between these sections, and we use them to locate constructor pointers.
#pragma section(".CRT$XIA",long,read)
#pragma section(".CRT$XIZ",long,read)
#pragma section(".CRT$XCA",long,read)
#pragma section(".CRT$XCZ",long,read)

// Put .CRT data into .rdata section
#pragma comment(linker, "/merge:.CRT=.rdata")

// Pointers surrounding constructors
__declspec(allocate(".CRT$XIA")) _PIFV __xi_a[] = { 0 };
__declspec(allocate(".CRT$XIZ")) _PIFV __xi_z[] = { 0 };
__declspec(allocate(".CRT$XCA")) _PVFV __xc_a[] = { 0 };
__declspec(allocate(".CRT$XCZ")) _PVFV __xc_z[] = { 0 };

extern __declspec(allocate(".CRT$XIA")) _PIFV __xi_a[];
extern __declspec(allocate(".CRT$XIZ")) _PIFV __xi_z[];    // C initializers
extern __declspec(allocate(".CRT$XCA")) _PVFV __xc_a[];
extern __declspec(allocate(".CRT$XCZ")) _PVFV __xc_z[];    // C++ initializers

// Call C constructors
static int _initterm_e(_PIFV * pfbegin, _PIFV * pfend) {
        int ret = 0;

        // walk the table of function pointers from the bottom up, until
        // the end is encountered.  Do not skip the first entry.  The initial
        // value of pfbegin points to the first valid entry.  Do not try to
        // execute what pfend points to.  Only entries before pfend are valid.
        while ( pfbegin < pfend  && ret == 0)
        {
            // if current table entry is non-NULL, call thru it.
            if ( *pfbegin != 0 )
                ret = (**pfbegin)();
            ++pfbegin;
        }

        return ret;
}

// Call C++ constructors
static void _initterm (_PVFV * pfbegin, _PVFV * pfend)
{
        // walk the table of function pointers from the bottom up, until
        // the end is encountered.  Do not skip the first entry.  The initial
        // value of pfbegin points to the first valid entry.  Do not try to
        // execute what pfend points to.  Only entries before pfend are valid.
        while ( pfbegin < pfend )
        {
            // if current table entry is non-NULL, call thru it.
            if ( *pfbegin != 0 )
                (**pfbegin)();
            ++pfbegin;
        }
}

// Call this function as soon as possible. Basically should be at the moment you
// jump into your C/C++ kernel. But keep in mind that kernel is not yet initialized,
// and you can't use a lot of stuff in your constructors!
bool CallConstructors() {
	// Do C initialization
	int initret = _initterm_e(__xi_a, __xi_z);
	if ( initret != 0 ) {
            return false;
	}

        // Do C++ initialization
        _initterm(__xc_a, __xc_z);
	return true;
}