bit stuffing

[vamsi]

hi every one, iam vamsi from bangalore.

iam doing project called HDLC. In that iam having problem with bit
stuffing. can any one send me the VHDL code for that.

BIT STUFFING:

In the entire data stream, whenaver a string of five consecutive 1's
is detected, this module inserts a '0' after five consecutive 1's to
achive data transparency.

iam doing bit stuffing for 20 bits, so if any one know the logic
behind it please forward to me.