diff --git a/common/kernel/sdc.cc b/common/kernel/sdc.cc
index 0fbfe690..214acc2f 100644
--- a/common/kernel/sdc.cc
+++ b/common/kernel/sdc.cc
@@ -21,6 +21,7 @@
 
 #include "log.h"
 #include "nextpnr.h"
+#include "timing_constraint.h"
 
 #include <algorithm>
 #include <iterator>
@@ -80,8 +81,8 @@ struct SdcEntity
 
 struct SdcValue
 {
-    SdcValue(const std::string &s) : is_string(true), str(s) {};
-    SdcValue(const std::vector<SdcEntity> &l) : is_string(false), list(l) {};
+    SdcValue(const std::string &s) : is_string(true), str(s){};
+    SdcValue(const std::vector<SdcEntity> &l) : is_string(false), list(l){};
 
     bool is_string;
     std::string str;             // simple string value
@@ -95,7 +96,7 @@ struct SDCParser
     int lineno = 1;
     Context *ctx;
 
-    SDCParser(const std::string &buf, Context *ctx) : buf(buf), ctx(ctx) {};
+    SDCParser(const std::string &buf, Context *ctx) : buf(buf), ctx(ctx){};
 
     inline bool eof() const { return pos == int(buf.size()); }
 
diff --git a/common/kernel/timing_contraint.h b/common/kernel/timing_contraint.h
new file mode 100644
index 00000000..e7e697eb
--- /dev/null
+++ b/common/kernel/timing_contraint.h
@@ -0,0 +1,73 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2024  rowanG077 <goemansrowan@gmail.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.
+ *
+ */
+
+#ifndef TIMING_CONSTRAINT_H
+#define TIMING_CONSTRAINT_H
+
+#include "nextpnr.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+struct FalsePath
+{
+};
+
+struct MinMaxDelay
+{
+    enum class Type
+    {
+        MAXDELAY,
+        MINDELAY
+    };
+
+    [[maybe_unused]] static const std::string type_to_str(Type typ)
+    {
+        switch (typ) {
+        case Type::MAXDELAY:
+            return "MAXDELAY";
+        case Type::MINDELAY:
+            return "MINDELAY";
+        default:
+            log_error("Impossible MinMaxDelay::Type");
+        }
+    }
+
+    Type type;
+    delay_t delay;
+    bool datapath_only;
+};
+
+struct MultiCycle
+{
+    size_t cycles;
+};
+
+using TimingException = std::variant<FalsePath, MinMaxDelay, MultiCycle>;
+
+struct PathConstraint
+{
+    TimingException exception;
+
+    pool<CellPortKey> from;
+    pool<CellPortKey> to;
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif