fix: check if an EOF has been set without an SOF in the Cocotb MFB mo…

…nitor

python/cocotbext/cocotbext/ofm/mfb/monitors.py

@@ -78,16 +78,19 @@ async def _monitor_recv(self):
                     self.log.debug(f"ee_idx {str(ee_idx)}")
                     self.log.debug(f"ss_idx {str(ss_idx)}")
 
-                    if (self._eof_arr[rr] == 1) and (in_frame):
-                        # Checks if there is a packet that is being processed and if it ends in this region.
-                        self.log.debug("Frame End")
-                        in_frame = False
-                        eof_done = True
-                        frame += data_bytes[rs_inx:ee_idx]
-                        self.item_cnt += len(data_bytes[rs_inx:ee_idx])*8 // self._item_width
-                        self.log.debug(f"frame done {frame.hex()}")
-                        self._recv(frame)
-                        self.frame_cnt += 1
+                    if self._eof_arr[rr] == 1:
+                        if in_frame:
+                            # Checks if there is a packet that is being processed and if it ends in this region.
+                            self.log.debug("Frame End")
+                            in_frame = False
+                            eof_done = True
+                            frame += data_bytes[rs_inx:ee_idx]
+                            self.item_cnt += len(data_bytes[rs_inx:ee_idx])*8 // self._item_width
+                            self.log.debug(f"frame done {frame.hex()}")
+                            self._recv(frame)
+                            self.frame_cnt += 1
+                        elif self._sof_arr[rr] == 1 and (self._eof_pos_arr[rr] < self._sof_pos_arr[rr]):
+                            raise MFBProtocolError("MFB error: an end-of-frame received before a start-of-frame!")
 
                     if in_frame:
                         # Region with a valid 'middle of packet'.