1 files changed, 130 insertions, 0 deletions
diff --git a/fpga_interchange/site_lut_mapping_cache.h b/fpga_interchange/site_lut_mapping_cache.h
new file mode 100644
index 00000000..4a81711f
--- /dev/null
+++ b/fpga_interchange/site_lut_mapping_cache.h
@@ -0,0 +1,130 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2021  Symbiflow Authors
+ *
+ *  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.
+ *
+ */
+
+#ifndef SITE_LUT_MAPPING_CACHE_H
+#define SITE_LUT_MAPPING_CACHE_H
+
+#include "idstring.h"
+#include "nextpnr_namespaces.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+// Key structure used in site LUT mapping cache
+struct SiteLutMappingKey {
+
+    // LUT Cell data
+    struct Cell {
+        IdString    type;       // Cell type
+        int32_t     belIndex;   // Bound BEL index
+  
+        // Port to net assignments. These are local net ids generated during
+        // key creation. This is to abstract connections from actual design
+        // net names.
+        dict<IdString, int32_t> conns;
+
+        bool operator == (const Cell& other) const {
+            return  (type == other.type) &&
+                    (belIndex == other.belIndex) &&
+                    (conns == other.conns);
+        }
+
+        bool operator < (const Cell& other) const {            
+            return belIndex < other.belIndex;
+        }
+    };
+
+    int32_t           tileType; // Tile type
+    int32_t           siteType; // Site type in that tile type
+    std::vector<Cell> cells;    // LUT cell data
+
+    static SiteLutMappingKey create (const SiteInformation& siteInfo);
+   
+    bool operator == (const SiteLutMappingKey &other) const {
+        return (tileType == other.tileType) &&
+               (siteType == other.siteType) &&
+               (cells == other.cells);
+    }
+
+    bool operator != (const SiteLutMappingKey &other) const {
+        return (tileType != other.tileType) ||
+               (siteType != other.siteType) ||
+               (cells != other.cells);
+    }
+
+    unsigned int hash () const {
+        unsigned int h = 0;
+        h = mkhash(h, tileType);
+        h = mkhash(h, siteType);
+        for (const auto& cell : cells) {
+            h = mkhash(h, cell.type.index);
+            h = mkhash(h, cell.belIndex);
+            for (const auto& conn : cell.conns) {
+                h = mkhash(h, conn.first.index);
+                h = mkhash(h, conn.second);
+            }
+        }
+        return h;
+    }
+};
+
+// Site LUT mapping result data
+struct SiteLutMappingResult {
+
+    // LUT cell data
+    struct Cell {
+        int32_t                     belIndex; // BEL in tile index
+        LutCell                     lutCell;  // LUT mapping data
+        dict<IdString, IdString>    belPins;  // Cell to BEL pin mapping
+    };
+
+    bool                isValid; // Validity flag
+    std::vector<Cell>   cells;   // Cell data
+
+    pool<std::pair<IdString, IdString>>  blockedWires;
+
+    // Applies the mapping result to the site
+    bool apply  (const SiteInformation& siteInfo);
+};
+
+// Site LUT mapping cache object
+class SiteLutMappingCache {
+public:
+
+    void add    (const SiteLutMappingKey& key, const SiteLutMappingResult& result);
+    bool get    (const SiteLutMappingKey& key, SiteLutMappingResult* result);
+
+    void clear      ();
+    void clearStats ();
+
+    float getMissRatio () const {
+        return (float)numMisses / (float)(numHits + numMisses);
+    }
+
+private:
+
+    dict<SiteLutMappingKey, SiteLutMappingResult> cache_;
+
+    size_t numHits   = 0;
+    size_t numMisses = 0;
+};
+
+
+NEXTPNR_NAMESPACE_END
+
+#endif /* SITE_LUT_MAPPING_CACHE_H */