From e1f72318e0b126de119cbc5e7f7b143e7beadd09 Mon Sep 17 00:00:00 2001
From: "William D. Jones" <thor0505@comcast.net>
Date: Sat, 30 Jan 2021 12:39:57 -0500
Subject: machxo2: Tweak A-star parameters for acceptable performance.

---
 machxo2/arch.cc | 20 ++++++++++++++++++--
 machxo2/arch.h  |  9 ++++++++-
 2 files changed, 26 insertions(+), 3 deletions(-)

(limited to 'machxo2')

diff --git a/machxo2/arch.cc b/machxo2/arch.cc
index 3410ec16..58c48044 100644
--- a/machxo2/arch.cc
+++ b/machxo2/arch.cc
@@ -365,9 +365,25 @@ const std::vector<GroupId> &Arch::getGroupGroups(GroupId group) const { return g
 
 // ---------------------------------------------------------------
 
-delay_t Arch::estimateDelay(WireId src, WireId dst) const { return 0; }
+delay_t Arch::estimateDelay(WireId src, WireId dst) const
+{
+    // Taxicab distance multiplied by pipDelay (0.01) and fake wireDelay (0.01).
+    // TODO: This function will not work well for entrance to global routing,
+    // as the entrances are located physically far from the DCCAs.
+    return (abs(dst.location.x - src.location.x) + abs(dst.location.y - src.location.y)) * (0.01 + 0.01);
+}
+
+delay_t Arch::predictDelay(const NetInfo *net_info, const PortRef &sink) const
+{
+    BelId src = net_info->driver.cell->bel;
+    BelId dst = sink.cell->bel;
+
+    NPNR_ASSERT(src != BelId());
+    NPNR_ASSERT(dst != BelId());
 
-delay_t Arch::predictDelay(const NetInfo *net_info, const PortRef &sink) const { return 0; }
+    // TODO: Same deal applies here as with estimateDelay.
+    return (abs(dst.location.x - src.location.x) + abs(dst.location.y - src.location.y)) * (0.01 + 0.01);
+}
 
 bool Arch::getBudgetOverride(const NetInfo *net_info, const PortRef &sink, delay_t &budget) const { return false; }
 
diff --git a/machxo2/arch.h b/machxo2/arch.h
index a438424f..8fdb63fc 100644
--- a/machxo2/arch.h
+++ b/machxo2/arch.h
@@ -850,7 +850,14 @@ struct Arch : BaseCtx
         return wire;
     }
 
-    DelayInfo getPipDelay(PipId pip) const { return DelayInfo(); }
+    DelayInfo getPipDelay(PipId pip) const
+    {
+        DelayInfo delay;
+
+        delay.delay = 0.01;
+
+        return delay;
+    }
 
     PipRange getPipsDownhill(WireId wire) const
     {
-- 
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