That is not a functionality that a block has already been written for, so you would need to write the C code yourself, and at best would be able to call into it.
Remember, C itself provides very limited I/O, with no device access, no access to absolute memory locations, no access to PORT assembly language instructions, and no bit-level I/O operations. Those things can be written using extensions to C such as #asm blocks or type-punning a long int to a pointer (C specifies the behavior of that to be undefined unless the integer is 0.)
