Simple implementation of IVL_EX_SELECT

tgt-vhdl/expr.cc

@@ -37,7 +37,7 @@ static vhdl_expr *translate_string(ivl_expr_t e)
  * A reference to a signal in an expression. It's assumed that the
  * signal has already been defined elsewhere.
  */
-static vhdl_expr *translate_signal(ivl_expr_t e)
+static vhdl_var_ref *translate_signal(ivl_expr_t e)
 {
    ivl_signal_t sig = ivl_expr_signal(e);
 
@@ -149,6 +149,8 @@ static vhdl_expr *translate_binary(ivl_expr_t e)
    switch (ivl_expr_opcode(e)) {
    case '+':
       return translate_numeric(lhs, rhs, VHDL_BINOP_ADD);
+   case '-':
+      return translate_numeric(lhs, rhs, VHDL_BINOP_SUB);
    case 'e':
       return translate_relation(lhs, rhs, VHDL_BINOP_EQ);
    case 'E':
@@ -186,6 +188,21 @@ static vhdl_expr *translate_binary(ivl_expr_t e)
    }
 }
 
+vhdl_expr *translate_select(ivl_expr_t e)
+{
+   vhdl_expr *from = translate_expr(ivl_expr_oper1(e));
+   if (NULL == from)
+      return NULL;   
+   
+   // Hack: resize it to the correct size
+   vhdl_type *rtype = vhdl_type::nsigned(ivl_expr_width(e));     
+   vhdl_fcall *resize = new vhdl_fcall("Resize", rtype);
+   resize->add_expr(from);
+   resize->add_expr(new vhdl_const_int(ivl_expr_width(e)));
+   
+   return resize;
+}
+
 /*
  * Generate a VHDL expression from a Verilog expression.
  */
@@ -205,6 +222,8 @@ vhdl_expr *translate_expr(ivl_expr_t e)
       return translate_unary(e);
    case IVL_EX_BINARY:
       return translate_binary(e);
+   case IVL_EX_SELECT:
+      return translate_select(e);
    default:
       error("No VHDL translation for expression at %s:%d (type = %d)",
             ivl_expr_file(e), ivl_expr_lineno(e), type);

tgt-vhdl/vhdl_syntax.cc

@@ -518,9 +518,20 @@ void vhdl_pcall_stmt::emit(std::ofstream &of, int level) const
    of << ";";
 }
 
+vhdl_var_ref::~vhdl_var_ref()
+{
+   if (slice_)
+      delete slice_;
+}
+
 void vhdl_var_ref::emit(std::ofstream &of, int level) const
 {
    of << name_;
+   if (slice_) {
+      of << "(";
+      slice_->emit(of, level);
+      of << ")";
+   }
 }
 
 void vhdl_const_string::emit(std::ofstream &of, int level) const

tgt-vhdl/vhdl_syntax.hh

@@ -40,17 +40,20 @@ private:
 
 
 /*
- * A normal scalar variable reference.
+ * A scalar or array variable reference.
  */
 class vhdl_var_ref : public vhdl_expr {
 public:
-   vhdl_var_ref(const char *name, vhdl_type *type)
+   vhdl_var_ref(const char *name, vhdl_type *type,
-      : vhdl_expr(type), name_(name) {}
+                vhdl_expr *slice = NULL)
+      : vhdl_expr(type), name_(name), slice_(slice) {}
+   ~vhdl_var_ref();
    
    void emit(std::ofstream &of, int level) const;
    const std::string &get_name() const { return name_; }
 private:
    std::string name_;
+   vhdl_expr *slice_;
 };