Neither the mod function call nor the sin function call are supported for HDL Code Generation inside the MATLAB Function block. Mod to a power of 2 can be done in hardware by choosing only the desired bits of the operand; a mod of 2*pi may be more difficult. You will need to carefully consider your data types and representation to achieve the desired functionality.
As for the sin function; it can be done in a MATLAB Function block, but not by calling the sin function. One of the product examples is entitled "CORDIC Algorithm Using the MATLAB® Function Block"; I suggest you investigate this to see what is involved. Perhaps a simpler alternative is to use the Trigonometric Function block, which can directly implement a CORDIC trig approximation in Simulink and in HDL Coder.
