mingw-w64-crt/intrincs/umul128ex.c

#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
#endif
#define __CRT__NO_INLINE
#include <windows.h>

/* for __x86_64 only */

DWORD64 UnsignedMultiplyExtract128(DWORD64 Multiplier,DWORD64 Multiplicand,BYTE Shift) {
      DWORD64 extractedProduct;
      DWORD64 highProduct;
      DWORD64 lowProduct;
      lowProduct = UnsignedMultiply128(Multiplier,Multiplicand,&highProduct);
      extractedProduct = ShiftRight128(lowProduct,highProduct,Shift);
      return extractedProduct;
}