The D3DDivide macro divides two values.
D3DDivide(a, b)    (float)((double) (a) / (double) (b)) 
 The macros returns the quotient of the division.
  Windows NT/2000: Requires Windows NT 4.0 SP3 or later.
  Windows 95/98: Requires Windows 95 or later. Available as a redistributable for Windows 95.
  Header: Declared in d3dtypes.h.