Refactor common placement functions out of SA placer for use in legaliser

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

1 files changed, 92 insertions, 0 deletions

diff --git a/common/place_common.cc b/common/place_common.cc
new file mode 100644
index 00000000..86060cd8
--- /dev/null
+++ b/common/place_common.cc
@@ -0,0 +1,92 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  David Shah <david@symbioticeda.com>
+ *
+ *  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 "place_common.h"
+#include <cmath>
+#include "log.h"
+#include "util.h"
+NEXTPNR_NAMESPACE_BEGIN
+
+// Get the total estimated wirelength for a net
+wirelen_t get_net_wirelength(const Context *ctx, const NetInfo *net, float &tns)
+{
+    wirelen_t wirelength = 0;
+    int driver_x, driver_y;
+    bool driver_gb;
+    CellInfo *driver_cell = net->driver.cell;
+    if (!driver_cell)
+        return 0;
+    if (driver_cell->bel == BelId())
+        return 0;
+    ctx->estimatePosition(driver_cell->bel, driver_x, driver_y, driver_gb);
+    WireId drv_wire = ctx->getWireBelPin(driver_cell->bel, ctx->portPinFromId(net->driver.port));
+    if (driver_gb)
+        return 0;
+    float worst_slack = 1000;
+    int xmin = driver_x, xmax = driver_x, ymin = driver_y, ymax = driver_y;
+    for (auto load : net->users) {
+        if (load.cell == nullptr)
+            continue;
+        CellInfo *load_cell = load.cell;
+        if (load_cell->bel == BelId())
+            continue;
+        if (ctx->timing_driven) {
+            WireId user_wire = ctx->getWireBelPin(load_cell->bel, ctx->portPinFromId(load.port));
+            delay_t raw_wl = ctx->estimateDelay(drv_wire, user_wire);
+            float slack = ctx->getDelayNS(load.budget) - ctx->getDelayNS(raw_wl);
+            if (slack < 0)
+                tns += slack;
+            worst_slack = std::min(slack, worst_slack);
+        }
+
+        int load_x, load_y;
+        bool load_gb;
+        ctx->estimatePosition(load_cell->bel, load_x, load_y, load_gb);
+        if (load_gb)
+            continue;
+        xmin = std::min(xmin, load_x);
+        ymin = std::min(ymin, load_y);
+        xmax = std::max(xmax, load_x);
+        ymax = std::max(ymax, load_y);
+    }
+    if (ctx->timing_driven) {
+        wirelength = wirelen_t((((ymax - ymin) + (xmax - xmin)) * std::min(5.0, (1.0 + std::exp(-worst_slack / 5)))));
+    } else {
+        wirelength = wirelen_t((ymax - ymin) + (xmax - xmin));
+    }
+
+    return wirelength;
+}
+
+// Get the total wirelength for a cell
+wirelen_t get_cell_wirelength(const Context *ctx, const CellInfo *cell)
+{
+    std::set<IdString> nets;
+    for (auto p : cell->ports) {
+        nets.insert(p.first);
+    }
+    wirelen_t wirelength = 0;
+    float tns = 0;
+    for (auto n : nets) {
+        wirelength += get_net_wirelength(ctx, ctx->nets.at(n).get(), tns);
+    }
+    return wirelength;
+}
+
+NEXTPNR_NAMESPACE_END