Thanks for reaching out to us.
As of now, only Intel IPPCP is open-sourced.
But you can find the source code for IPP TL(Threading Layer) functions if you install Intel oneAPI Base Toolkit from where you can get Intel IPP library. Please refer to the following link for more details.
As we haven't heard back from you, we are closing this case. Please post a new question if you need any additional assistance from Intel as this thread will no longer be monitored.