code: def rotate_shift_mask_simplifier(a, b):
          
  
          # is the second argument a BVV?
          if b.op != 'BVV':
              return None
  
          # is it a rotate-shift?
          if a.op != '__or__' or len(a.args) != 2:
              return None
          a_0, a_1 = a.args
  
          if a_0.op != '__lshift__':
              return None
          if a_1.op != 'LShR':
              return None
          a_00, a_01 = a_0.args
          a_10, a_11 = a_1.args
          if not a_00 is a_10:
              return None
          if a_01.op != 'BVV' or a_11.op != 'BVV':
              return None
          lshift_ = a_01.args[0]
          rshift_ = a_11.args[0]
          bitwidth = lshift_ + rshift_
          if bitwidth not in (32, 64):
              return None
  
          # is the second argument a mask?
          # Note: the following check can be further loosen if we want to support more masks.
          if bitwidth == 32:
              m = ((b.args[0] << rshift_) & 0xffffffff) | (b.args[0] >> lshift_)
              if m != 0xffff:
                  return None
          else: # bitwidth == 64
              m = ((b.args[0] << rshift_) & 0xffffffffffffffff) | (b.args[0] >> lshift_)
              if m != 0xffffffff:
                  return None
  
          # Show our power!
          masked_a = (a_00 & m)
          expr = (masked_a << lshift_) | (masked_a >> rshift_)
          return expr
docs: Handles the following case:
              ((A << a) | (A >> (_N - a))) & mask, where
                  A being a BVS,
                  a being a integer that is less than _N,
                  _N is either 32 or 64, and
                  mask can be evaluated to 0xffffffff (64-bit) or 0xffff (32-bit) after reversing the rotate-shift
                  operation.
  
          It will be simplified to:
              (A & (mask >>> a)) <<< a