Range unset mask

//Unset range of bits
//For e.g. 1001 1001
//Unset bits from 2 to 5 i.e. 1 0 0 1 1 0 0 1 => 10 0000 01
//                               |- - - -| 
//                      Bits  7 6 5 4 3 2 1 0          
//
//Step1
//------
//To unset range of bits we need to create MASK
// val  = 1001 1001
// Mask = 1100 0011 (AND)
//      _____________
//        1000 0001
//
//Step 2
//-------
//We need to construct MASK
//In MASK, bits in range are 0 i.e. bits from 2-5 is 0 and
//rest of the bits are 1
// MASK 1 1 0 0 0 0 1 1
//         |- - - -|
// Bits 7 6 5 4 3 2 1 0
//
//Step 3
//-------
// 0 0 0 1  1 1 1 1  ((1 << 5) - 1) i.e. (1 << j) - 1
//
//MAX  1 1 1 1  1 1 1 1
//     0 0 1 1  1 1 1 1  (-)
//    ------------------
//     1 1 0 0  0 0 0 0         =====> (1)
//
// (1 << 2) - 1 i.e. (1 << i) - 1
// 0 0 0 0 0 1 0 0
// 0 0 0 0 0 0 0 1 (-)
//------------------
// 0 0 0 0 0 0 1 1              =====> (2)
//
// (1) OR (2)
// 1 1 0 0 0 0 0 0
// 0 0 0 0 0 0 1 1   (OR)
//-------------------
// 1 1 0 0 0 0 1 1 
//
//Final Step
// val  = 1001 1001
// Mask = 1100 0011 (AND)
//      _____________
//        1000 0001