Fix fsm style subroutine return going to wrong state with nested no return func calls. Also remove extra long transition list state machine for extra clocks in state transitions when executed

Author: JulianKemmerer

src/C_TO_FSM.py

@@ -521,12 +521,17 @@ def STATE_GROUP_TO_C_CODE(
             text += "  }\n"
             continue
 
-        # At this point the stage is absolutely empty, assume to be delay state for delaying return
-        #raise Exception("Need assumed delay state for return?")
-        text += "    // ASSUMED EMPTY DELAY STATE FOR RETURN\n"
-        text += "    FSM_STATE = RETURN_REG;\n"
-        text += "    FUNC_CALL_RETURN_FSM_STATE = ENTRY_REG;\n"
-        text += "  }\n"
+        # At this point the stage assumed to be returning/done?
+        # From a subroutine or main?
+        if state_info.sub_func_name is not None:
+            text += "    // Assumed subroutine returning to scheduled return state\n"
+            text += "    FSM_STATE = " + state_info.sub_func_name + "_FUNC_CALL_RETURN_FSM_STATE;\n"
+            text += "  }\n"
+        else:
+            text += "    // ASSUMED EMPTY DELAY STATE FOR RETURN\n"
+            text += "    FSM_STATE = RETURN_REG;\n"
+            text += "    FUNC_CALL_RETURN_FSM_STATE = ENTRY_REG;\n"
+            text += "  }\n"
 
     return text
 
@@ -995,7 +1000,7 @@ def GET_STATE_TRANS_LISTS(start_state, parser_state, visited_states=None):
     # print()
     # visited_states is primarily to resolve loops for user instead of requiring __clk()?
     if start_state in visited_states:
-        return [[start_state]]
+        return [[]] #[[start_state]]
     visited_states.append(start_state)
 
     debug = False
@@ -1784,7 +1789,8 @@ def GET_GROUPED_STATE_TRANSITIONS(
         return []
     state_groups = [None] * (max(state_to_latest_index.values()) + 1)
     for state, index in state_to_latest_index.items():
-        # print("Last Index",index,state.name)
+        if debug:
+            print("Last Index",index,state.name)
         if state_groups[index] is None:
             state_groups[index] = set()
         state_groups[index].add(state)