First passing at blocking assignment

tgt-vhdl/process.cc

@@ -24,13 +24,15 @@
 #include <iostream>
 #include <cassert>
 #include <sstream>
+#include <set>
 
 /*
  * TODO: Explanation here.
  */
-static string_list_t g_assign_vars;
+typedef std::set<std::string> string_set_t;
+static string_set_t g_assign_vars;
 
-void blocking_assign_to(std::string var)
+void blocking_assign_to(vhdl_process *proc, std::string var)
 {
    std::cout << "blocking_assign_to " << var << std::endl;
 }

tgt-vhdl/stmt.cc

@@ -178,9 +178,13 @@ static int draw_noop(vhdl_process *proc, stmt_container *container,
    return 0;
 }
 
-template <class T>
+/*
-static int draw_generic_assign(vhdl_process *proc, stmt_container *container,
+ * A non-blocking assignment inside a process. The semantics for
-                               ivl_statement_t stmt, vhdl_expr *after = NULL)
+ * this are essentially the same as VHDL's non-blocking signal
+ * assignment.
+ */
+static int draw_nbassign(vhdl_process *proc, stmt_container *container,
+                         ivl_statement_t stmt, vhdl_expr *after = NULL)
 {
    int nlvals = ivl_stmt_lvals(stmt);
    if (nlvals != 1) {
@@ -218,7 +222,7 @@ static int draw_generic_assign(vhdl_process *proc, stmt_container *container,
          // The type here can be null as it is never actually needed
          vhdl_var_ref *lval_ref = new vhdl_var_ref(signame, NULL);
          
-         T *assign = new T(lval_ref, rhs);
+         vhdl_nbassign_stmt *assign = new vhdl_nbassign_stmt(lval_ref, rhs);
          if (after != NULL)
             assign->set_after(after);
          container->add_stmt(assign);
@@ -232,22 +236,47 @@ static int draw_generic_assign(vhdl_process *proc, stmt_container *container,
    return 0;
 }
 
-/*
- * A non-blocking assignment inside a process. The semantics for
- * this are essentially the same as VHDL's non-blocking signal
- * assignment.
- */
-static int draw_nbassign(vhdl_process *proc, stmt_container *container,
-                         ivl_statement_t stmt, vhdl_expr *after = NULL)
-{
-   return draw_generic_assign<vhdl_nbassign_stmt>
-      (proc, container, stmt, after);
-}
-
 static int draw_assign(vhdl_process *proc, stmt_container *container,
                        ivl_statement_t stmt)
 {
-   
+   int nlvals = ivl_stmt_lvals(stmt);
+   if (nlvals != 1) {
+      error("Can only have 1 lval at the moment (found %d)", nlvals);
+      return 1;
+   }
+
+   ivl_lval_t lval = ivl_stmt_lval(stmt, 0);
+   ivl_signal_t sig;
+   if ((sig = ivl_lval_sig(lval))) {
+      const std::string &signame = get_renamed_signal(sig);
+
+      blocking_assign_to(proc, signame);
+
+      vhdl_decl *decl = proc->get_decl(signame);
+      assert(decl);
+
+      vhdl_expr *rhs_raw = translate_expr(ivl_stmt_rval(stmt));
+      if (NULL == rhs_raw)
+         return 1;
+      vhdl_expr *rhs = rhs_raw->cast(decl->get_type());
+
+      // As with non-blocking assignment, push assignments into the
+      // initialisation if we can
+      if (proc->is_initial() && ivl_signal_port(sig) == IVL_SIP_NONE) {
+         decl->set_initial(rhs);
+      }
+      else {
+         // The type here can be null as it is never actually needed
+         vhdl_var_ref *lval_ref = new vhdl_var_ref(signame.c_str(), NULL);
+         
+         vhdl_assign_stmt *assign = new vhdl_assign_stmt(lval_ref, rhs);
+         container->add_stmt(assign);
+      }
+   }
+   else {
+      error("Only signals as lvals supported at the moment");
+      return 1;
+   }
    
    return 0;
 }

tgt-vhdl/vhdl_syntax.cc

@@ -202,6 +202,19 @@ void vhdl_process::add_decl(vhdl_decl* decl)
    decls_.push_back(decl);
 }
 
+vhdl_decl *vhdl_process::get_decl(const std::string &name) const
+{
+   decl_list_t::const_iterator it;
+   for (it = decls_.begin(); it != decls_.end(); ++it) {
+      if ((*it)->get_name() == name)
+         return *it;
+   }
+
+   // Maybe it's a signal rather than a variable?
+   assert(get_parent());
+   return get_parent()->get_decl(name);
+}
+
 void vhdl_process::add_sensitivity(const char *name)
 {
    sens_.push_back(name);
@@ -548,6 +561,14 @@ void vhdl_nbassign_stmt::emit(std::ofstream &of, int level) const
    of << ";";
 }
 
+void vhdl_assign_stmt::emit(std::ofstream &of, int level) const
+{
+   lhs_->emit(of, level);
+   of << " := ";
+   rhs_->emit(of, level);
+   of << ";";
+}
+
 vhdl_const_bits::vhdl_const_bits(const char *value, int width)   
    : vhdl_expr(vhdl_type::nsigned(width))
 {

tgt-vhdl/vhdl_syntax.hh

@@ -256,6 +256,15 @@ public:
 };
 
 
+class vhdl_assign_stmt : public vhdl_abstract_assign_stmt {
+public:
+   vhdl_assign_stmt(vhdl_var_ref *lhs, vhdl_expr *rhs)
+      : vhdl_abstract_assign_stmt(lhs, rhs) {}
+
+   void emit(std::ofstream &of, int level) const;
+};
+
+
 enum vhdl_wait_type_t {
    VHDL_WAIT_INDEF,    // Suspend indefinitely
    VHDL_WAIT_FOR_NS,   // Wait for a constant number of nanoseconds
@@ -456,6 +465,7 @@ public:
    void add_decl(vhdl_decl *decl);
    void add_sensitivity(const char *name);
    bool have_declared_var(const std::string &name) const;
+   vhdl_decl *get_decl(const std::string &name) const;
    void set_initial(bool i) { initial_ = i; }
    bool is_initial() const { return initial_; }
 private:

tgt-vhdl/vhdl_target.h

@@ -31,7 +31,7 @@ void rename_signal(ivl_signal_t sig, const std::string &renamed);
 const vhdl_entity *find_entity_for_signal(ivl_signal_t sig);
 const std::string &get_renamed_signal(ivl_signal_t sig);
 
-void blocking_assign_to(std::string var);
+void blocking_assign_to(vhdl_process *proc, std::string var);
 
 
 #endif /* #ifndef INC_VHDL_TARGET_H */