From c064ae6bc37e89c2b4879340051b67fb42cc522f Mon Sep 17 00:00:00 2001
From: Nick Gasson <nick@nickg.me.uk>
Date: Sat, 7 Jun 2008 14:54:00 +0100
Subject: [PATCH] Generate VHDL for non-blocking assignments

---
 tgt-vhdl/stmt.cc         | 32 +++++++++++++++++++++++++++++++-
 tgt-vhdl/vhdl_element.cc |  9 +++++++++
 tgt-vhdl/vhdl_element.hh |  5 ++++-
 3 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/tgt-vhdl/stmt.cc b/tgt-vhdl/stmt.cc
index eb96339e9..636c4f283 100644
--- a/tgt-vhdl/stmt.cc
+++ b/tgt-vhdl/stmt.cc
@@ -153,7 +153,37 @@ static int draw_noop(vhdl_process *proc, ivl_statement_t stmt)
  */
 static int draw_nbassign(vhdl_process *proc, ivl_statement_t stmt)
 {
-   std::cout << "draw_nbassign" << std::endl;
+   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 char *signame = ivl_signal_basename(sig);
+
+      vhdl_expr *rhs = translate_expr(ivl_stmt_rval(stmt));
+      if (NULL == rhs)
+         return 1;
+      
+      vhdl_decl *decl = proc->get_parent()->get_decl(signame);
+      assert(decl);
+      
+      vhdl_type *lval_type = decl->get_type()->clone();
+      vhdl_var_ref *lval_ref = new vhdl_var_ref(signame, lval_type);
+      
+      // TODO: Internal sanity check:
+      //   ensure rhs->get_type() == lval_type
+
+      proc->add_stmt(new vhdl_nbassign_stmt(lval_ref, rhs));
+   }
+   else {
+      error("Only signals as lvals supported at the moment");
+      return 1;
+   }
+   
    return 0;
 }
 
diff --git a/tgt-vhdl/vhdl_element.cc b/tgt-vhdl/vhdl_element.cc
index 2411be773..a3b499a95 100644
--- a/tgt-vhdl/vhdl_element.cc
+++ b/tgt-vhdl/vhdl_element.cc
@@ -343,6 +343,15 @@ void vhdl_wait_stmt::emit(std::ofstream &of, int level) const
    of << "wait;";
 }
 
+/*
+ * Create a deep copy of this type, so it can appear in more
+ * than one place in the AST.
+ */
+vhdl_type *vhdl_scalar_type::clone() const
+{
+   return new vhdl_scalar_type(name_.c_str());
+}
+
 vhdl_scalar_type *vhdl_scalar_type::std_logic()
 {
    return new vhdl_scalar_type("std_logic");
diff --git a/tgt-vhdl/vhdl_element.hh b/tgt-vhdl/vhdl_element.hh
index 0a44e9a6d..28d38b6bf 100644
--- a/tgt-vhdl/vhdl_element.hh
+++ b/tgt-vhdl/vhdl_element.hh
@@ -54,6 +54,8 @@ public:
    vhdl_type(const char *name) : name_(name) {}
    virtual ~vhdl_type() {}
 
+   virtual vhdl_type *clone() const = 0;
+
    const std::string &get_name() const { return name_; }
 protected:
    std::string name_;
@@ -70,6 +72,7 @@ public:
       : vhdl_type(name) {}
 
    void emit(std::ofstream &of, int level) const;
+   vhdl_type *clone() const;
 
    // Common types
    static vhdl_scalar_type *std_logic();
@@ -179,7 +182,7 @@ public:
    vhdl_nbassign_stmt(vhdl_var_ref *lhs, vhdl_expr *rhs)
       : lhs_(lhs), rhs_(rhs) {}
 
-   void emit(std::ofstream &of, int level);
+   void emit(std::ofstream &of, int level) const;
 private:
    vhdl_var_ref *lhs_;
    vhdl_expr *rhs_;