RtlDWordPtrMult - NtDoc

#ifndef _NTINTSAFE_H_INCLUDED_
#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP | WINAPI_PARTITION_SYSTEM | WINAPI_PARTITION_GAMES)
//
// DWORD_PTR multiplication
//
#ifdef _WIN64

#define RtlDWordPtrMult    RtlULongLongMult

#endif
#endif
#endif
View code on GitHub

#ifndef _NTINTSAFE_H_INCLUDED_
#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP | WINAPI_PARTITION_SYSTEM | WINAPI_PARTITION_GAMES)
//
// DWORD_PTR multiplication
//
#ifdef _WIN64
// ...
#else

_Must_inspect_result_
__inline
NTSTATUS
RtlDWordPtrMult(
    _In_ DWORD_PTR dwMultiplicand,
    _In_ DWORD_PTR dwMultiplier,
    _Out_ _Deref_out_range_(==, dwMultiplicand * dwMultiplier) DWORD_PTR* pdwResult)
{
    ULONGLONG ull64Result = UInt32x32To64(dwMultiplicand, dwMultiplier);
    
    return RtlULongLongToDWordPtr(ull64Result, pdwResult);
}

#endif
#endif
#endif
View code on GitHub