Each `jmp` to f0..fX is an optimisation of a `call` and a `ret`, and probably done in a separate pass after the switch-case code has already been expanded.
The `mov edi, esi` at the top of the function is also an optimisation, most likely done during the register allocation pass.
This was only possible because all functions take the same value in the same register. Otherwise, there would probably have been also a `mov` before each of the calls.
Each `jmp` to f0..fX is an optimisation of a `call` and a `ret`, and probably done in a separate pass after the switch-case code has already been expanded.
The `mov edi, esi` at the top of the function is also an optimisation, most likely done during the register allocation pass. This was only possible because all functions take the same value in the same register. Otherwise, there would probably have been also a `mov` before each of the calls.