First approach (CHIP-8)

void chip8_cycle(Chip8 *vm)
{
    vm->ticks++;
    fetch_decode_and_execute(vm);
}

int main(int argc, char *argv[])
{
    if (argc != 3) {
        SDL_Log("Usage: %s <instr-per-sec> <rom-file>", argv[0]);
        return 1;
    }

    // Instructions per second executed by the VM (e.g. 540)
    int ips = SDL_atoi(argv[1]);

    // Read ROM file ...

    Chip8 vm;
    chip8_init(&vm);
    chip8_load_rom(&vm, rom, rom_size);

    // If ips=540 clock_delay=1.85ms and timers_period=9
    double clock_delay = 1000.0 / ips;
    int timers_period = ips / 60;

    // Initialize graphics ...

    while (true) {
        Uint64 start = SDL_GetPerformanceCounter();

       // Handle input event ...

        chip8_cycle(&vm);

        // If ips=540 decrease the timers every 9th instruction
        if (vm.ticks % timers_period == 0)
            chip8_decrease_timers(&vm);

        // If executed instruction == 0xDxyn (DRAW) update graphics
        if ((vm.opcode & 0xF000) == 0xD000)
            // Update graphics ...

        Uint64 end = SDL_GetPerformanceCounter();
        double frequency = (double) SDL_GetPerformanceFrequency();
        double elapsed_time = ((end - start) * 1000) / frequency;

        if (elapsed_time < clock_delay)
            SDL_Delay((Uint32) (clock_delay - elapsed_time));
    }

    return 0;
}