Comment by rhengles

Forgive me for replying here, I couldn't find an option to DM you. And I cannot find any implementation of this in javascript, nor anyone else able to help me.

Can you shed some light here why I'm getting these differences?

https://jsfiddle.net/7kf15dje/

Here is an example of the output I'm getting:

  //       X  A  B           X^1         X^-1 :: Difference
   471490377  6 13 =  1365552781 =  471490377 :: 0
  1528396978  9 11 = -1576695076 = 1528396978 :: -0
  1592322722  9 20 =   622346385 = 1592322722 :: -0
  1214152986  8 16 = -1748578289 = 1214152985 :: -1
  1193897367  2 16 =   907713766 = 1193897366 :: -1
   335642564  9 10 =   318891964 =  335642564 :: -0
   486208953 16 23 =   894211128 =  486208952 :: -1
   629577059 13 14 =  1383225523 =  629577058 :: -1
  1609442937  8 18 =   674046110 = 1609442937 :: -0
   234450967  6 12 =  -459008694 =  234450966 :: -1
  1840721644 19 28 =  -602984005 = 1840721644 :: -0