Generate rising/falling edge detectors

tgt-vhdl/stmt.cc

@@ -238,8 +238,6 @@ static int draw_delay(vhdl_process *proc, stmt_container *container,
 /*
  * A wait statement waits for a level change on a @(..) list of
  * signals.
- * TODO: This won't yet handle the posedge to rising_edge, etc.
- * mapping.
  */
 static int draw_wait(vhdl_process *proc, stmt_container *container,
                      ivl_statement_t stmt)
@@ -248,10 +246,9 @@ static int draw_wait(vhdl_process *proc, stmt_container *container,
    for (int i = 0; i < nevents; i++) {
       ivl_event_t event = ivl_stmt_events(stmt, i);
 
-      if (ivl_event_nneg(event) != 0)
-         error("Negative edge events not supported yet");
-      if (ivl_event_npos(event) != 0)
-         error("Positive edge events not supported yet");
+      // A list of the non-edge triggered signals to they can
+      // be added to the edge-detecting `if' statement later
+      string_list_t non_edges;
 
       int nany = ivl_event_nany(event);
       for (int i = 0; i < nany; i++) {
@@ -268,14 +265,77 @@ static int draw_wait(vhdl_process *proc, stmt_container *container,
                // Only add this signal to the sensitivity if it's part
                // of the containing architecture (i.e. it has already
                // been declared)
-               if (proc->get_parent()->have_declared(signame))
+               if (proc->get_parent()->have_declared(signame)) {
                   proc->add_sensitivity(signame);
+                  non_edges.push_back(signame);
+               }
             }
             else {
                // Ignore all other types of nexus pointer
             }
          }
-      }         
+      }
+
+      int nneg = ivl_event_nneg(event);
+      int npos = ivl_event_npos(event);
+      if (nneg + npos > 0) {
+         vhdl_binop_expr *test =
+            new vhdl_binop_expr(VHDL_BINOP_OR, vhdl_type::boolean());
+
+         // Generate falling_edge(..) calls for each negedge event
+         for (int i = 0; i < nneg; i++) {
+            ivl_nexus_t nexus = ivl_event_neg(event, i);
+
+            int nptrs = ivl_nexus_ptrs(nexus);
+            for (int j = 0; j < nptrs; j++) {
+               ivl_nexus_ptr_t nexus_ptr = ivl_nexus_ptr(nexus, j);
+
+               ivl_signal_t sig;
+               if ((sig = ivl_nexus_ptr_sig(nexus_ptr))) {
+                  vhdl_fcall *detect
+                     = new vhdl_fcall("falling_edge", vhdl_type::boolean());
+                  detect->add_expr
+                     (new vhdl_var_ref(ivl_signal_basename(sig),
+                                       vhdl_type::std_logic()));
+                  test->add_expr(detect);
+               }
+            }
+         }
+
+         // Generate rising_edge(..) calls for each posedge event
+         for (int i = 0; i < npos; i++) {
+            ivl_nexus_t nexus = ivl_event_pos(event, i);
+
+            int nptrs = ivl_nexus_ptrs(nexus);
+            for (int j = 0; j < nptrs; j++) {
+               ivl_nexus_ptr_t nexus_ptr = ivl_nexus_ptr(nexus, j);
+
+               ivl_signal_t sig;
+               if ((sig = ivl_nexus_ptr_sig(nexus_ptr))) {
+                  vhdl_fcall *detect
+                     = new vhdl_fcall("rising_edge", vhdl_type::boolean());
+                  detect->add_expr
+                     (new vhdl_var_ref(ivl_signal_basename(sig),
+                                       vhdl_type::std_logic()));
+                  test->add_expr(detect);
+               }
+            }
+         }
+
+         // Add Name'Event terms for each non-edge-triggered signal
+         string_list_t::iterator it;
+         for (it = non_edges.begin(); it != non_edges.end(); ++it) {
+            test->add_expr
+               (new vhdl_var_ref((*it + "'Event").c_str(),
+                                 vhdl_type::boolean()));
+         }
+         
+         container->add_stmt(new vhdl_if_stmt(test));
+      }
+      else {
+         // Don't bother generating an edge detector if there
+         // are no edge-triggered events
+      }
    }
 
    ivl_statement_t sub_stmt = ivl_stmt_sub_stmt(stmt);

tgt-vhdl/vhdl_syntax.hh

@@ -163,7 +163,6 @@ private:
    vhdl_expr_list exprs_;
 };
 
-
 /*
  * A concurrent statement appears in architecture bodies but not
  * processes.

tgt-vhdl/vhdl_type.cc

@@ -38,6 +38,11 @@ vhdl_type *vhdl_type::line()
    return new vhdl_type(VHDL_TYPE_LINE);
 }
 
+vhdl_type *vhdl_type::boolean()
+{
+   return new vhdl_type(VHDL_TYPE_BOOLEAN);
+}
+
 vhdl_type *vhdl_type::integer()
 {
    return new vhdl_type(VHDL_TYPE_INTEGER);

tgt-vhdl/vhdl_type.hh

@@ -30,6 +30,7 @@ enum vhdl_type_name_t {
    VHDL_TYPE_LINE,
    VHDL_TYPE_FILE,
    VHDL_TYPE_INTEGER,
+   VHDL_TYPE_BOOLEAN,
 };
 
 /*
@@ -54,6 +55,7 @@ public:
    static vhdl_type *line();
    static vhdl_type *std_logic_vector(int msb, int lsb);
    static vhdl_type *integer();
+   static vhdl_type *boolean();
 protected:
    vhdl_type_name_t name_;
    int msb_, lsb_;