Sliding windows implementation (Exponentiation by squaring) I am conducting a research on cpu-cache based info leak caused by using Sliding window in the diffie helman key exchange.

For my research I am looking for a real-world implementation of sliding window,I have read the source of BouncyCastle and Gnu-TLs and came out empty.

Can someone share some light on the real world use of this algorithm and where, if at all I will be able to find implementation of it?
Serious cryptography software today does not use sliding windows for exponentiation by secrets precisely because it leaks the secrets through array indexing.  You might find it older versions of OpenSSL, libgcrypt, etc.  In modern software, your best bet is probably libgmp (mpz_powm, not mpz_powm_sec) or other generic bignum libraries optimized for speed, not for security.