#-------------------------------------------------------------------------------

func floorLog2* (x : int) : int = 
  var k = -1
  var y = x
  while (y > 0):
    k += 1
    y = y shr 1
  return k

func ceilingLog2* (x : int) : int = 
  if (x==0):
    return -1
  else:
    return (floorLog2(x-1) + 1)

#
# import std/math
#
# proc sanityCheckLog2* () =
#   for i in 0..18:
#     let x = float64(i)
#     echo( i," | ",floorLog2(i),"=",floor(log2(x))," | ",ceilingLog2(i),"=",ceil(log2(x)) )
#

#-------------------------------------------------------------------------------