The RSHIFT and RSHFT predeclared functions return a value of the
  same  type  as  its  first  parameter.  The value represents the
  value of the first parameter after the bits have been shifted to
  the right.

  Syntax:

     RSHIFT(expression,expression)
     RSHFT(expression,expression)

  The parameters are two integer or unsigned  values.   The  first
  parameter represents a value to shift; the second represents the
  number of bits to shift the first value.  The RSHIFT  and  RSHFT
  functions insert zero bits on the left as the bits shift right.

  Note that shifting integers is not equivalent to multiplying  or
  dividing  by  a  power  of  two when the value of the integer is
  negative.

  If the number of bits shifted is larger than the natural integer
  size of the target platform, the result is undefined.