From 43c671cb5c8757145c4daf63b3af33e145950ebc Mon Sep 17 00:00:00 2001
From: Nick Gasson <nick@nickg.me.uk>
Date: Wed, 25 Jun 2008 18:00:48 +0100
Subject: [PATCH] Emit VHDL for function declarations

---
 tgt-vhdl/scope.cc       |  9 +++++++--
 tgt-vhdl/vhdl_syntax.cc | 29 +++++++++++++++++++++++++++++
 tgt-vhdl/vhdl_syntax.hh | 22 +++++++++++++++++-----
 3 files changed, 53 insertions(+), 7 deletions(-)

diff --git a/tgt-vhdl/scope.cc b/tgt-vhdl/scope.cc
index 237b77d64..049ab1141 100644
--- a/tgt-vhdl/scope.cc
+++ b/tgt-vhdl/scope.cc
@@ -377,9 +377,14 @@ int draw_function(ivl_scope_t scope, ivl_scope_t parent)
    vhdl_entity *ent = find_entity(ivl_scope_tname(parent));
    assert(ent);
 
-   return 1;
-}
+   const char *funcname = ivl_scope_tname(scope);
 
+   vhdl_function *func = new vhdl_function(funcname, vhdl_type::std_logic());
+
+   ent->get_arch()->get_scope()->add_decl(func);
+   
+   return 0;
+}
 
 int draw_scope(ivl_scope_t scope, void *_parent)
 {
diff --git a/tgt-vhdl/vhdl_syntax.cc b/tgt-vhdl/vhdl_syntax.cc
index 921f15964..d8bdb95ed 100644
--- a/tgt-vhdl/vhdl_syntax.cc
+++ b/tgt-vhdl/vhdl_syntax.cc
@@ -751,3 +751,32 @@ void vhdl_while_stmt::emit(std::ofstream &of, int level) const
    stmts_.emit(of, level);
    of << "end loop;";
 }
+
+vhdl_function::vhdl_function(const char *name, vhdl_type *ret_type)
+   : vhdl_decl(name, ret_type)
+{
+   // A function contains two scopes:
+   //  scope_ = The paramters
+   //  variables_ = Local variables
+   // A call to get_scope returns variables_ whose parent is scope_
+   variables_.set_parent(&scope_);
+}
+
+void vhdl_function::emit(std::ofstream &of, int level) const
+{
+   of << "function " << name_ << " (";
+   emit_children<vhdl_decl>(of, scope_.get_decls(), level, ",");
+   of << ") return ";
+   type_->emit(of, level);
+   of << " is";
+   emit_children<vhdl_decl>(of, variables_.get_decls(), level);
+   of << "begin";
+   stmts_.emit(of, level);
+   of << "end function;";
+}
+
+void vhdl_param_decl::emit(std::ofstream &of, int level) const
+{
+   of << name_ << " : ";
+   type_->emit(of, level);
+}
diff --git a/tgt-vhdl/vhdl_syntax.hh b/tgt-vhdl/vhdl_syntax.hh
index 742a38f5d..463a637b4 100644
--- a/tgt-vhdl/vhdl_syntax.hh
+++ b/tgt-vhdl/vhdl_syntax.hh
@@ -467,6 +467,16 @@ public:
 };
 
 
+/*
+ * A parameter to a function.
+ */
+class vhdl_param_decl : public vhdl_decl {
+public:
+   vhdl_param_decl(const char *name, vhdl_type *type)
+      : vhdl_decl(name, type) {}
+   void emit(std::ofstream &of, int level) const;
+};
+
 enum vhdl_port_mode_t {
    VHDL_PORT_IN,
    VHDL_PORT_OUT,
@@ -553,8 +563,8 @@ class vhdl_procedural {
 public:
    virtual ~vhdl_procedural() {}
    
-   stmt_container *get_container() { return &stmts_; }
-   vhdl_scope *get_scope() { return &scope_; }
+   virtual stmt_container *get_container() { return &stmts_; }
+   virtual vhdl_scope *get_scope() { return &scope_; }
 protected:
    stmt_container stmts_;
    vhdl_scope scope_;
@@ -563,11 +573,13 @@ protected:
 
 class vhdl_function : public vhdl_decl, public vhdl_procedural {
 public:
-   vhdl_function(const char *name, vhdl_type *ret_type)
-      : vhdl_decl(name, ret_type) {}
-
+   vhdl_function(const char *name, vhdl_type *ret_type);
+   
    void emit(std::ofstream &of, int level) const;
+   vhdl_scope *get_scope() { return &variables_; }
+   void add_param(vhdl_param_decl *p) { scope_.add_decl(p); }
 private:
+   vhdl_scope variables_;
 };