SQL Standard Core Based License

I have a server with 32 cores. I need to purchase SQL Standard 2014 for this server. SQL Standard 2014 supports maximum of 16 cores. Is there any way of utilising all of 32 cores of server.

For eg. If I purchase 16 core license and install 2 instances of SQL Standard on the server. Will both instances use same 16 cores or different 16 cores.

Also 1 question is if I can install multiple instances of SQL on same server machine with single license. So to install I will need to purchase 8*2core packs or 16*2 core packs. Assuming I am using processor affinity to use all 32 cores of the server.