Adding some utilities for packing

Signed-off-by: David Shah <davey1576@gmail.com>

1 files changed, 60 insertions, 0 deletions

diff --git a/common/design_utils.h b/common/design_utils.h
new file mode 100644
index 00000000..2faceddc
--- /dev/null
+++ b/common/design_utils.h
@@ -0,0 +1,60 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Clifford Wolf <clifford@clifford.at>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "nextpnr.h"
+
+/*
+Utilities for design manipulation, intended for use inside packing algorithms
+ */
+
+// Disconnect a net (if connected) from old, and connect it to rep
+void replace_port(CellInfo *old_cell, PortInfo *old, CellInfo *rep_cell,
+                  PortInfo *rep);
+
+// If a net drives a given port of a cell matching a predicate (in many
+// cases more than one cell type, e.g. SB_DFFxx so a predicate is used), return
+// the first instance of that cell (otherwise nullptr). If exclusive is set to
+// true, then this cell must be the only load
+template <typename F1>
+CellInfo *net_only_drives(NetInfo *net, F1 cell_pred, IdString port,
+                          bool exclusive = false)
+{
+    if (exclusive && (net->users.size() != 1)) {
+        return nullptr;
+    } else {
+        for (const auto &load : net->users) {
+            if (cell_pred(load.cell) && load.port == port) {
+                return load.cell;
+            }
+        }
+        return nullptr;
+    }
+}
+
+// If a net is driven by a given port of a cell matching a predicate, return
+// that cell, otherwise nullptr
+template <typename F1>
+CellInfo *net_driven_by(NetInfo *net, F1 cell_pred, IdString port)
+{
+    if (cell_pred(net->driver.cell) && net->driver.port == port) {
+        return net->driver.cell;
+    } else {
+        return nullptr;
+    }
+}