MATLAB: What is block in simulink

Question

Anybody please let me know what name of this block ? Where is this block in the library of simulink? (This is file simiam.mdl of the Sim.I.am simulation. You can download it with link https://www.mathworks.com/matlabcentral/fileexchange/40860-sim-i-am)

Answer 1

They are all S-function blocks -> User-definable block written using the MATLAB S-Function API.

To learn more about MATLAB S-function, check this link .

All the respected S-function files are listed in the file exchange download (inside the Simulink folder)