From 081f3974604b961809dbf19ebb94d2d22be49608 Mon Sep 17 00:00:00 2001
From: Nick Gasson <nick@nickg.me.uk>
Date: Fri, 27 Jun 2008 14:58:03 +0100
Subject: [PATCH] Implement LPM part select

---
 tgt-vhdl/lpm.cc         | 26 ++++++++++++++++++++++++++
 tgt-vhdl/vhdl_syntax.hh |  1 +
 2 files changed, 27 insertions(+)

diff --git a/tgt-vhdl/lpm.cc b/tgt-vhdl/lpm.cc
index 3d67ddf93..00f7240e1 100644
--- a/tgt-vhdl/lpm.cc
+++ b/tgt-vhdl/lpm.cc
@@ -58,6 +58,30 @@ static int draw_binop_lpm(vhdl_arch *arch, ivl_lpm_t lpm, vhdl_binop_t op)
    return 0;
 }
 
+int draw_part_select_lpm(vhdl_arch *arch, ivl_lpm_t lpm)
+{
+   vhdl_var_ref *selfrom = nexus_to_var_ref(arch->get_scope(), ivl_lpm_data(lpm, 0));
+   if (NULL == selfrom)
+      return 1;
+   
+   vhdl_expr *off = nexus_to_var_ref(arch->get_scope(), ivl_lpm_data(lpm, 1));
+   if (NULL == off)
+      return 1;
+
+   vhdl_var_ref *out = nexus_to_var_ref(arch->get_scope(), ivl_lpm_q(lpm, 0));
+   if (NULL == out)
+      return 1;
+
+   // Array indexes must be integers
+   vhdl_type integer(VHDL_TYPE_INTEGER);
+   off = off->cast(&integer);
+
+   selfrom->set_slice(off);
+   arch->add_stmt(new vhdl_cassign_stmt(out, selfrom));
+   
+   return 0;
+}
+
 int draw_lpm(vhdl_arch *arch, ivl_lpm_t lpm)
 {
    switch (ivl_lpm_type(lpm)) {
@@ -67,6 +91,8 @@ int draw_lpm(vhdl_arch *arch, ivl_lpm_t lpm)
       return draw_binop_lpm(arch, lpm, VHDL_BINOP_SUB);
    case IVL_LPM_MULT:
       return draw_binop_lpm(arch, lpm, VHDL_BINOP_MULT);
+   case IVL_LPM_PART_VP:
+      return draw_part_select_lpm(arch, lpm);
    default:
       error("Unsupported LPM type: %d", ivl_lpm_type(lpm));
       return 1;
diff --git a/tgt-vhdl/vhdl_syntax.hh b/tgt-vhdl/vhdl_syntax.hh
index d650d2cd6..16cf8109a 100644
--- a/tgt-vhdl/vhdl_syntax.hh
+++ b/tgt-vhdl/vhdl_syntax.hh
@@ -56,6 +56,7 @@ public:
    
    void emit(std::ofstream &of, int level) const;
    const std::string &get_name() const { return name_; }
+   void set_slice(vhdl_expr *s) { slice_ = s; }
 private:
    std::string name_;
    vhdl_expr *slice_;