riscv/remote_bitbang.h

   1 #ifndef REMOTE_BITBANG_H
   2 #define REMOTE_BITBANG_H
   3
   4 #include <stdint.h>
   5
   6 class sim_t;
   7
   8 template <typename T>
   9 class circular_buffer_t
  10 {
  11 public:
  12   // The buffer can store capacity-1 data elements.
  13   circular_buffer_t(unsigned int capacity) : data(new T[capacity]),
  14       start(0), end(0), capacity(capacity) {}
  15   circular_buffer_t() : start(0), end(0), capacity(0) {}
  16   ~circular_buffer_t() { delete[] data; }
  17
  18   T *data;
  19   unsigned int start;   // Data start, inclusive.
  20   unsigned int end;     // Data end, exclusive.
  21   unsigned int capacity;    // Size of the buffer.
  22   unsigned int size() const;
  23   bool empty() const { return start == end; }
  24   bool full() const { return ((end+1) % capacity) == start; }
  25   T entry(unsigned index) { return data[(start + index) % capacity]; }
  26
  27   // Return size and address of the block of RAM where more data can be copied
  28   // to be added to the buffer.
  29   unsigned int contiguous_empty_size() const;
  30   T *contiguous_empty() { return data + end; }
  31   void data_added(unsigned int bytes);
  32
  33   unsigned int contiguous_data_size() const;
  34   T *contiguous_data() { return data + start; }
  35   // Tell the buffer that some bytes were consumed from the start of the
  36   // buffer.
  37   void consume(unsigned int bytes);
  38
  39   void reset();
  40
  41   T operator[](unsigned int i) const { return data[(start + i) % capacity]; }
  42
  43   void append(const T *src, unsigned int count);
  44 };
  45
  46 class remote_bitbang_t
  47 {
  48 public:
  49   // Create a new server, listening for connections from localhost on the given
  50   // port.
  51   remote_bitbang_t(uint16_t port, sim_t *sim);
  52
  53   // Do a bit of work.
  54   void tick();
  55
  56 private:
  57   int socket_fd;
  58   int client_fd;
  59   circular_buffer_t<uint8_t> recv_buf;
  60   circular_buffer_t<uint8_t> send_buf;
  61
  62   // Check for a client connecting, and accept if there is one.
  63   void accept();
  64   // Read as much into recv_buf as possible.
  65   void read();
  66   // Write as much of send_buf as possible.
  67   void write();
  68 };
  69
  70 #endif