29 files changed, 1270 insertions, 913 deletions

diff --git a/common/command.cc b/common/command.cc
new file mode 100644
index 00000000..736f6201
--- /dev/null
+++ b/common/command.cc
@@ -0,0 +1,263 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Clifford Wolf <clifford@symbioticeda.com>
+ *  Copyright (C) 2018  Miodrag Milanovic <miodrag@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.
+ *
+ */
+
+#ifndef NO_GUI
+#include <QApplication>
+#include "application.h"
+#include "mainwindow.h"
+#endif
+#ifndef NO_PYTHON
+#include "pybindings.h"
+#endif
+
+#include <boost/filesystem/convenience.hpp>
+#include <boost/program_options.hpp>
+#include <fstream>
+#include <iostream>
+#include "command.h"
+#include "design_utils.h"
+#include "jsonparse.h"
+#include "log.h"
+#include "timing.h"
+#include "version.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+CommandHandler::CommandHandler(int argc, char **argv) : argc(argc), argv(argv) { log_files.push_back(stdout); }
+
+bool CommandHandler::parseOptions()
+{
+    options.add(getGeneralOptions()).add(getArchOptions());
+    try {
+        po::parsed_options parsed =
+                po::command_line_parser(argc, argv)
+                        .style(po::command_line_style::default_style ^ po::command_line_style::allow_guessing)
+                        .options(options)
+                        .positional(pos)
+                        .run();
+        po::store(parsed, vm);
+        po::notify(vm);
+        return true;
+    } catch (std::exception &e) {
+        std::cout << e.what() << "\n";
+        return false;
+    }
+}
+
+bool CommandHandler::executeBeforeContext()
+{
+    if (vm.count("help") || argc == 1) {
+        std::cout << boost::filesystem::basename(argv[0])
+                  << " -- Next Generation Place and Route (git sha1 " GIT_COMMIT_HASH_STR ")\n";
+        std::cout << options << "\n";
+        return argc != 1;
+    }
+
+    if (vm.count("version")) {
+        std::cout << boost::filesystem::basename(argv[0])
+                  << " -- Next Generation Place and Route (git sha1 " GIT_COMMIT_HASH_STR ")\n";
+        return true;
+    }
+    validate();
+    return false;
+}
+
+po::options_description CommandHandler::getGeneralOptions()
+{
+    po::options_description general("General options");
+    general.add_options()("help,h", "show help");
+    general.add_options()("verbose,v", "verbose output");
+    general.add_options()("debug", "debug output");
+    general.add_options()("force,f", "keep running after errors");
+#ifndef NO_GUI
+    general.add_options()("gui", "start gui");
+#endif
+#ifndef NO_PYTHON
+    general.add_options()("run", po::value<std::vector<std::string>>(), "python file to execute");
+    pos.add("run", -1);
+#endif
+    general.add_options()("json", po::value<std::string>(), "JSON design file to ingest");
+    general.add_options()("seed", po::value<int>(), "seed value for random number generator");
+    general.add_options()("slack_redist_iter", po::value<int>(), "number of iterations between slack redistribution");
+    general.add_options()("cstrweight", po::value<float>(), "placer weighting for relative constraint satisfaction");
+    general.add_options()("pack-only", "pack design only without placement or routing");
+
+    general.add_options()("version,V", "show version");
+    general.add_options()("test", "check architecture database integrity");
+    general.add_options()("freq", po::value<double>(), "set target frequency for design in MHz");
+    general.add_options()("no-tmdriv", "disable timing-driven placement");
+    general.add_options()("save", po::value<std::string>(), "project file to write");
+    general.add_options()("load", po::value<std::string>(), "project file to read");
+    return general;
+}
+
+void CommandHandler::setupContext(Context *ctx)
+{
+    if (vm.count("verbose")) {
+        ctx->verbose = true;
+    }
+
+    if (vm.count("debug")) {
+        ctx->verbose = true;
+        ctx->debug = true;
+    }
+
+    if (vm.count("force")) {
+        ctx->force = true;
+    }
+
+    if (vm.count("seed")) {
+        ctx->rngseed(vm["seed"].as<int>());
+    }
+
+    if (vm.count("slack_redist_iter")) {
+        ctx->slack_redist_iter = vm["slack_redist_iter"].as<int>();
+        if (vm.count("freq") && vm["freq"].as<double>() == 0) {
+            ctx->auto_freq = true;
+#ifndef NO_GUI
+            if (!vm.count("gui"))
+#endif
+                log_warning("Target frequency not specified. Will optimise for max frequency.\n");
+        }
+    }
+
+    if (vm.count("cstrweight")) {
+        // ctx->placer_constraintWeight = vm["cstrweight"].as<float>();
+    }
+
+    if (vm.count("freq")) {
+        auto freq = vm["freq"].as<double>();
+        if (freq > 0)
+            ctx->target_freq = freq * 1e6;
+    }
+
+    ctx->timing_driven = true;
+    if (vm.count("no-tmdriv"))
+        ctx->timing_driven = false;
+}
+
+int CommandHandler::executeMain(std::unique_ptr<Context> ctx)
+{
+    if (vm.count("test")) {
+        ctx->archcheck();
+        return 0;
+    }
+
+#ifndef NO_GUI
+    if (vm.count("gui")) {
+        Application a(argc, argv);
+        MainWindow w(std::move(ctx), chipArgs);
+        try {
+            if (vm.count("json")) {
+                std::string filename = vm["json"].as<std::string>();
+                std::ifstream f(filename);
+                if (!parse_json_file(f, filename, w.getContext()))
+                    log_error("Loading design failed.\n");
+
+                customAfterLoad(w.getContext());
+                w.updateJsonLoaded();
+            }
+        } catch (log_execution_error_exception) {
+            // show error is handled by gui itself
+        }
+        w.show();
+
+        return a.exec();
+    }
+#endif
+    if (vm.count("json")) {
+        std::string filename = vm["json"].as<std::string>();
+        std::ifstream f(filename);
+        if (!parse_json_file(f, filename, ctx.get()))
+            log_error("Loading design failed.\n");
+
+        customAfterLoad(ctx.get());
+    }
+
+    if (vm.count("json") || vm.count("load")) {
+        if (!ctx->pack() && !ctx->force)
+            log_error("Packing design failed.\n");
+        assign_budget(ctx.get());
+        ctx->check();
+        print_utilisation(ctx.get());
+        if (!vm.count("pack-only")) {
+            if (!ctx->place() && !ctx->force)
+                log_error("Placing design failed.\n");
+            ctx->check();
+            if (!ctx->route() && !ctx->force)
+                log_error("Routing design failed.\n");
+        }
+
+        customBitstream(ctx.get());
+    }
+
+#ifndef NO_PYTHON
+    if (vm.count("run")) {
+        init_python(argv[0], true);
+        python_export_global("ctx", *ctx);
+
+        std::vector<std::string> files = vm["run"].as<std::vector<std::string>>();
+        for (auto filename : files)
+            execute_python_file(filename.c_str());
+
+        deinit_python();
+    }
+#endif
+
+    if (vm.count("save")) {
+        project.save(ctx.get(), vm["save"].as<std::string>());
+    }
+
+    return 0;
+}
+
+void CommandHandler::conflicting_options(const boost::program_options::variables_map &vm, const char *opt1,
+                                         const char *opt2)
+{
+    if (vm.count(opt1) && !vm[opt1].defaulted() && vm.count(opt2) && !vm[opt2].defaulted()) {
+        std::string msg = "Conflicting options '" + std::string(opt1) + "' and '" + std::string(opt2) + "'.";
+        log_error("%s\n", msg.c_str());
+    }
+}
+
+int CommandHandler::exec()
+{
+    try {
+        if (!parseOptions())
+            return -1;
+
+        if (executeBeforeContext())
+            return 0;
+
+        std::unique_ptr<Context> ctx;
+        if (vm.count("load")) {
+            ctx = project.load(vm["load"].as<std::string>());
+        } else {
+            ctx = createContext();
+        }
+        setupContext(ctx.get());
+        setupArchContext(ctx.get());
+        return executeMain(std::move(ctx));
+    } catch (log_execution_error_exception) {
+        return -1;
+    }
+}
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/command.h b/common/command.h
new file mode 100644
index 00000000..13d5a250
--- /dev/null
+++ b/common/command.h
@@ -0,0 +1,70 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Clifford Wolf <clifford@symbioticeda.com>
+ *  Copyright (C) 2018  Miodrag Milanovic <miodrag@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.
+ *
+ */
+
+#ifndef COMMAND_H
+#define COMMAND_H
+
+#include <boost/program_options.hpp>
+#include "nextpnr.h"
+#include "project.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+namespace po = boost::program_options;
+
+class CommandHandler
+{
+  public:
+    CommandHandler(int argc, char **argv);
+    virtual ~CommandHandler(){};
+
+    int exec();
+
+  protected:
+    virtual void setupArchContext(Context *ctx) = 0;
+    virtual std::unique_ptr<Context> createContext() = 0;
+    virtual po::options_description getArchOptions() = 0;
+    virtual void validate(){};
+    virtual void customAfterLoad(Context *ctx){};
+    virtual void customBitstream(Context *ctx){};
+    void conflicting_options(const boost::program_options::variables_map &vm, const char *opt1, const char *opt2);
+
+  private:
+    bool parseOptions();
+    bool executeBeforeContext();
+    void setupContext(Context *ctx);
+    int executeMain(std::unique_ptr<Context> ctx);
+    po::options_description getGeneralOptions();
+
+  protected:
+    po::variables_map vm;
+    ArchArgs chipArgs;
+
+  private:
+    po::options_description options;
+    po::positional_options_description pos;
+    int argc;
+    char **argv;
+    ProjectHandler project;
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif // COMMAND_H
diff --git a/common/nextpnr.h b/common/nextpnr.h
index f231f1b8..e588f47b 100644
--- a/common/nextpnr.h
+++ b/common/nextpnr.h
@@ -291,6 +291,19 @@ struct CellInfo : ArchCellInfo
     // parent.[xyz] := 0 when (constr_parent == nullptr)
 };
 
+enum TimingPortClass
+{
+    TMG_CLOCK_INPUT,     // Clock input to a sequential cell
+    TMG_GEN_CLOCK,       // Generated clock output (PLL, DCC, etc)
+    TMG_REGISTER_INPUT,  // Input to a register, with an associated clock (may also have comb. fanout too)
+    TMG_REGISTER_OUTPUT, // Output from a register
+    TMG_COMB_INPUT,      // Combinational input, no paths end here
+    TMG_COMB_OUTPUT,     // Combinational output, no paths start here
+    TMG_STARTPOINT,      // Unclocked primary startpoint, such as an IO cell output
+    TMG_ENDPOINT,        // Unclocked primary endpoint, such as an IO cell input
+    TMG_IGNORE,          // Asynchronous to all clocks, "don't care", and should be ignored (false path) for analysis
+};
+
 struct DeterministicRNG
 {
     uint64_t rngstate;
@@ -371,6 +384,9 @@ struct BaseCtx
     mutable std::unordered_map<std::string, int> *idstring_str_to_idx;
     mutable std::vector<const std::string *> *idstring_idx_to_str;
 
+    // Project settings and config switches
+    std::unordered_map<IdString, std::string> settings;
+
     // Placed nets and cells.
     std::unordered_map<IdString, std::unique_ptr<NetInfo>> nets;
     std::unordered_map<IdString, std::unique_ptr<CellInfo>> cells;
@@ -437,7 +453,7 @@ struct BaseCtx
 
     const Context *getCtx() const { return reinterpret_cast<const Context *>(this); }
 
-    template<typename T> const char *nameOf(const T *obj)
+    template <typename T> const char *nameOf(const T *obj)
     {
         if (obj == nullptr)
             return "";
diff --git a/common/placer1.cc b/common/placer1.cc
index 36a607d7..91320240 100644
--- a/common/placer1.cc
+++ b/common/placer1.cc
@@ -236,7 +236,10 @@ class SAPlacer
                 temp = post_legalise_temp;
                 diameter *= post_legalise_dia_scale;
                 ctx->shuffle(autoplaced);
-                assign_budget(ctx);
+
+                // Legalisation is a big change so force a slack redistribution here
+                if (ctx->slack_redist_iter > 0)
+                    assign_budget(ctx, true /* quiet */);
             } else if (ctx->slack_redist_iter > 0 && iter % ctx->slack_redist_iter == 0) {
                 assign_budget(ctx, true /* quiet */);
             }
diff --git a/common/project.cc b/common/project.cc
new file mode 100644
index 00000000..244ca761
--- /dev/null
+++ b/common/project.cc
@@ -0,0 +1,86 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Miodrag Milanovic <miodrag@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 "project.h"
+#include <boost/filesystem/convenience.hpp>
+#include <boost/property_tree/json_parser.hpp>
+#include <fstream>
+#include "jsonparse.h"
+#include "log.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+void ProjectHandler::save(Context *ctx, std::string filename)
+{
+    std::ofstream f(filename);
+    pt::ptree root;
+    root.put("project.version", 1);
+    root.put("project.name", boost::filesystem::basename(filename));
+    root.put("project.arch.name", ctx->archId().c_str(ctx));
+    root.put("project.arch.type", ctx->archArgsToId(ctx->archArgs()).c_str(ctx));
+    /*  root.put("project.input.json", );*/
+    root.put("project.params.freq", int(ctx->target_freq / 1e6));
+    root.put("project.params.seed", ctx->rngstate);
+    saveArch(ctx, root);
+    pt::write_json(f, root);
+}
+
+std::unique_ptr<Context> ProjectHandler::load(std::string filename)
+{
+    std::unique_ptr<Context> ctx;
+    try {
+        pt::ptree root;
+        boost::filesystem::path proj(filename);
+        pt::read_json(filename, root);
+        log_info("Loading project %s...\n", filename.c_str());
+        log_break();
+
+        int version = root.get<int>("project.version");
+        if (version != 1)
+            log_error("Wrong project format version.\n");
+
+        ctx = createContext(root);
+
+        std::string arch_name = root.get<std::string>("project.arch.name");
+        if (arch_name != ctx->archId().c_str(ctx.get()))
+            log_error("Unsuported project architecture.\n");
+
+        auto project = root.get_child("project");
+        auto input = project.get_child("input");
+        std::string filename = input.get<std::string>("json");
+        boost::filesystem::path json = proj.parent_path() / filename;
+        std::ifstream f(json.string());
+        if (!parse_json_file(f, filename, ctx.get()))
+            log_error("Loading design failed.\n");
+
+        if (project.count("params")) {
+            auto params = project.get_child("params");
+            if (params.count("freq"))
+                ctx->target_freq = params.get<double>("freq") * 1e6;
+            if (params.count("seed"))
+                ctx->rngseed(params.get<uint64_t>("seed"));
+        }
+        loadArch(ctx.get(), root, proj.parent_path().string());
+    } catch (...) {
+        log_error("Error loading project file.\n");
+    }
+    return ctx;
+}
+
+NEXTPNR_NAMESPACE_END
diff --git a/common/project.h b/common/project.h
new file mode 100644
index 00000000..14f03ecd
--- /dev/null
+++ b/common/project.h
@@ -0,0 +1,42 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Miodrag Milanovic <miodrag@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.
+ *
+ */
+
+#ifndef PROJECT_H
+#define PROJECT_H
+
+#include <boost/property_tree/ptree.hpp>
+#include "nextpnr.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+namespace pt = boost::property_tree;
+
+struct ProjectHandler
+{
+    void save(Context *ctx, std::string filename);
+    std::unique_ptr<Context> load(std::string filename);
+    // implemented per arch
+    void saveArch(Context *ctx, pt::ptree &root);
+    std::unique_ptr<Context> createContext(pt::ptree &root);
+    void loadArch(Context *ctx, pt::ptree &root, std::string path);
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif // PROJECT_H
diff --git a/common/timing.cc b/common/timing.cc
index c00e1ba5..aadd8381 100644
--- a/common/timing.cc
+++ b/common/timing.cc
@@ -20,6 +20,7 @@
 
 #include "timing.h"
 #include <algorithm>
+#include <boost/range/adaptor/reversed.hpp>
 #include <unordered_map>
 #include <utility>
 #include "log.h"
@@ -36,10 +37,18 @@ struct Timing
     bool net_delays;
     bool update;
     delay_t min_slack;
-    PortRefVector current_path;
     PortRefVector *crit_path;
     DelayFrequency *slack_histogram;
 
+    struct TimingData
+    {
+        TimingData() : max_arrival(), max_path_length(), min_remaining_budget() {}
+        TimingData(delay_t max_arrival) : max_arrival(max_arrival), max_path_length(), min_remaining_budget() {}
+        delay_t max_arrival;
+        unsigned max_path_length = 0;
+        delay_t min_remaining_budget;
+    };
+
     Timing(Context *ctx, bool net_delays, bool update, PortRefVector *crit_path = nullptr,
            DelayFrequency *slack_histogram = nullptr)
             : ctx(ctx), net_delays(net_delays), update(update), min_slack(1.0e12 / ctx->target_freq),
@@ -47,93 +56,246 @@ struct Timing
     {
     }
 
-    delay_t follow_net(NetInfo *net, int path_length, delay_t slack)
+    delay_t walk_paths()
     {
-        const delay_t default_budget = slack / (path_length + 1);
-        delay_t net_budget = default_budget;
-        for (auto &usr : net->users) {
-            auto delay = net_delays ? ctx->getNetinfoRouteDelay(net, usr) : delay_t();
-            if (crit_path)
-                current_path.push_back(&usr);
-            // If budget override exists, use that value and do not increment path_length
-            auto budget = default_budget;
-            if (ctx->getBudgetOverride(net, usr, budget)) {
-                if (update)
-                    usr.budget = std::min(usr.budget, budget);
-                budget = follow_user_port(usr, path_length, slack - budget);
-                net_budget = std::min(net_budget, budget);
+        const auto clk_period = delay_t(1.0e12 / ctx->target_freq);
+
+        // First, compute the topographical order of nets to walk through the circuit, assuming it is a _acyclic_ graph
+        // TODO(eddieh): Handle the case where it is cyclic, e.g. combinatorial loops
+        std::vector<NetInfo *> topographical_order;
+        std::unordered_map<const NetInfo *, TimingData> net_data;
+        // In lieu of deleting edges from the graph, simply count the number of fanins to each output port
+        std::unordered_map<const PortInfo *, unsigned> port_fanin;
+
+        std::vector<IdString> input_ports;
+        std::vector<const PortInfo *> output_ports;
+        for (auto &cell : ctx->cells) {
+            input_ports.clear();
+            output_ports.clear();
+            for (auto &port : cell.second->ports) {
+                if (!port.second.net)
+                    continue;
+                if (port.second.type == PORT_OUT)
+                    output_ports.push_back(&port.second);
+                else
+                    input_ports.push_back(port.first);
             }
-            else {
-                budget = follow_user_port(usr, path_length + 1, slack - delay);
-                net_budget = std::min(net_budget, budget);
-                if (update)
-                    usr.budget = std::min(usr.budget, delay + budget);
+
+            for (auto o : output_ports) {
+                IdString clockPort;
+                TimingPortClass portClass = ctx->getPortTimingClass(cell.second.get(), o->name, clockPort);
+                // If output port is influenced by a clock (e.g. FF output) then add it to the ordering as a timing
+                // start-point
+                if (portClass == TMG_REGISTER_OUTPUT) {
+                    DelayInfo clkToQ;
+                    ctx->getCellDelay(cell.second.get(), clockPort, o->name, clkToQ);
+                    topographical_order.emplace_back(o->net);
+                    net_data.emplace(o->net, TimingData{clkToQ.maxDelay()});
+                } else {
+                    // TODO(eddieh): Generated clocks and ignored ports are currently added into the ordering as if it
+                    // was a regular timing start point in order to enable the full topographical order to be computed,
+                    // however these false nets (and their downstream paths) should not be in the final ordering
+                    if (portClass == TMG_STARTPOINT || portClass == TMG_GEN_CLOCK || portClass == TMG_IGNORE) {
+                        topographical_order.emplace_back(o->net);
+                        net_data.emplace(o->net, TimingData{});
+                    }
+                    // Otherwise, for all driven input ports on this cell, if a timing arc exists between the input and
+                    // the current output port, increment fanin counter
+                    for (auto i : input_ports) {
+                        DelayInfo comb_delay;
+                        bool is_path = ctx->getCellDelay(cell.second.get(), i, o->name, comb_delay);
+                        if (is_path)
+                            port_fanin[o]++;
+                    }
+                }
             }
-            if (crit_path)
-                current_path.pop_back();
         }
-        return net_budget;
-    }
 
-    // Follow a path, returning budget to annotate
-    delay_t follow_user_port(PortRef &user, int path_length, delay_t slack)
-    {
-        delay_t value;
-        if (ctx->getPortClock(user.cell, user.port) != IdString()) {
-            // At the end of a timing path (arguably, should check setup time
-            // here too)
-            value = slack / path_length;
-            if (slack < min_slack) {
-                min_slack = slack;
-                if (crit_path)
-                    *crit_path = current_path;
+        // If these constant nets exist, add them to the topographical ordering too
+        // TODO(eddieh): Also false paths and should be removed from ordering
+        auto it = ctx->nets.find(ctx->id("$PACKER_VCC_NET"));
+        if (it != ctx->nets.end()) {
+            topographical_order.emplace_back(it->second.get());
+            net_data.emplace(it->second.get(), TimingData{});
+        }
+        it = ctx->nets.find(ctx->id("$PACKER_GND_NET"));
+        if (it != ctx->nets.end()) {
+            topographical_order.emplace_back(it->second.get());
+            net_data.emplace(it->second.get(), TimingData{});
+        }
+
+        std::deque<NetInfo *> queue(topographical_order.begin(), topographical_order.end());
+
+        // Now walk the design, from the start points identified previously, building up a topographical order
+        while (!queue.empty()) {
+            const auto net = queue.front();
+            queue.pop_front();
+
+            for (auto &usr : net->users) {
+                IdString clockPort;
+                TimingPortClass usrClass = ctx->getPortTimingClass(usr.cell, usr.port, clockPort);
+                if (usrClass == TMG_IGNORE || usrClass == TMG_CLOCK_INPUT)
+                    continue;
+                for (auto &port : usr.cell->ports) {
+                    if (port.second.type != PORT_OUT || !port.second.net)
+                        continue;
+                    TimingPortClass portClass = ctx->getPortTimingClass(usr.cell, port.first, clockPort);
+
+                    // Skip if this is a clocked output (but allow non-clocked ones)
+                    if (portClass == TMG_REGISTER_OUTPUT || portClass == TMG_STARTPOINT || portClass == TMG_IGNORE ||
+                        portClass == TMG_GEN_CLOCK)
+                        continue;
+                    DelayInfo comb_delay;
+                    bool is_path = ctx->getCellDelay(usr.cell, usr.port, port.first, comb_delay);
+                    if (!is_path)
+                        continue;
+                    // Decrement the fanin count, and only add to topographical order if all its fanins have already
+                    // been visited
+                    auto it = port_fanin.find(&port.second);
+                    NPNR_ASSERT(it != port_fanin.end());
+                    if (--it->second == 0) {
+                        topographical_order.emplace_back(port.second.net);
+                        queue.emplace_back(port.second.net);
+                        port_fanin.erase(it);
+                    }
+                }
             }
-            if (slack_histogram) {
-                int slack_ps = ctx->getDelayNS(slack) * 1000;
-                (*slack_histogram)[slack_ps]++;
+        }
+
+        // Sanity check to ensure that all ports where fanins were recorded were indeed visited
+        NPNR_ASSERT(port_fanin.empty());
+
+        // Go forwards topographically to find the maximum arrival time and max path length for each net
+        for (auto net : topographical_order) {
+            auto &nd = net_data.at(net);
+            const auto net_arrival = nd.max_arrival;
+            const auto net_length_plus_one = nd.max_path_length + 1;
+            nd.min_remaining_budget = clk_period;
+            for (auto &usr : net->users) {
+                IdString clockPort;
+                TimingPortClass portClass = ctx->getPortTimingClass(usr.cell, usr.port, clockPort);
+                if (portClass == TMG_REGISTER_INPUT || portClass == TMG_ENDPOINT || portClass == TMG_IGNORE) {
+                } else {
+                    auto net_delay = net_delays ? ctx->getNetinfoRouteDelay(net, usr) : delay_t();
+                    auto budget_override = ctx->getBudgetOverride(net, usr, net_delay);
+                    auto usr_arrival = net_arrival + net_delay;
+                    // Iterate over all output ports on the same cell as the sink
+                    for (auto port : usr.cell->ports) {
+                        if (port.second.type != PORT_OUT || !port.second.net)
+                            continue;
+                        DelayInfo comb_delay;
+                        // Look up delay through this path
+                        bool is_path = ctx->getCellDelay(usr.cell, usr.port, port.first, comb_delay);
+                        if (!is_path)
+                            continue;
+                        auto &data = net_data[port.second.net];
+                        auto &arrival = data.max_arrival;
+                        arrival = std::max(arrival, usr_arrival + comb_delay.maxDelay());
+                        if (!budget_override) { // Do not increment path length if budget overriden since it doesn't
+                                                // require a share of the slack
+                            auto &path_length = data.max_path_length;
+                            path_length = std::max(path_length, net_length_plus_one);
+                        }
+                    }
+                }
             }
-        } else {
-            // Default to the path ending here, if no further paths found
-            value = slack / path_length;
-            // Follow outputs of the user
-            for (auto port : user.cell->ports) {
-                if (port.second.type == PORT_OUT) {
-                    DelayInfo comb_delay;
-                    // Look up delay through this path
-                    bool is_path = ctx->getCellDelay(user.cell, user.port, port.first, comb_delay);
-                    if (is_path) {
-                        NetInfo *net = port.second.net;
-                        if (net) {
-                            delay_t path_budget = follow_net(net, path_length, slack - comb_delay.maxDelay());
-                            value = std::min(value, path_budget);
+        }
+
+        const NetInfo *crit_net = nullptr;
+
+        // Now go backwards topographically to determine the minimum path slack, and to distribute all path slack evenly
+        // between all nets on the path
+        for (auto net : boost::adaptors::reverse(topographical_order)) {
+            auto &nd = net_data.at(net);
+            const delay_t net_length_plus_one = nd.max_path_length + 1;
+            auto &net_min_remaining_budget = nd.min_remaining_budget;
+            for (auto &usr : net->users) {
+                auto net_delay = net_delays ? ctx->getNetinfoRouteDelay(net, usr) : delay_t();
+                auto budget_override = ctx->getBudgetOverride(net, usr, net_delay);
+                IdString associatedClock;
+                TimingPortClass portClass = ctx->getPortTimingClass(usr.cell, usr.port, associatedClock);
+                if (portClass == TMG_REGISTER_INPUT || portClass == TMG_ENDPOINT) {
+                    const auto net_arrival = nd.max_arrival;
+                    auto path_budget = clk_period - (net_arrival + net_delay);
+                    if (update) {
+                        auto budget_share = budget_override ? 0 : path_budget / net_length_plus_one;
+                        usr.budget = std::min(usr.budget, net_delay + budget_share);
+                        net_min_remaining_budget = std::min(net_min_remaining_budget, path_budget - budget_share);
+                    }
+
+                    if (path_budget < min_slack) {
+                        min_slack = path_budget;
+                        if (crit_path) {
+                            crit_path->clear();
+                            crit_path->push_back(&usr);
+                            crit_net = net;
                         }
                     }
+                    if (slack_histogram) {
+                        int slack_ps = ctx->getDelayNS(path_budget) * 1000;
+                        (*slack_histogram)[slack_ps]++;
+                    }
+                } else if (update) {
+                    // Iterate over all output ports on the same cell as the sink
+                    for (const auto &port : usr.cell->ports) {
+                        if (port.second.type != PORT_OUT || !port.second.net)
+                            continue;
+                        DelayInfo comb_delay;
+                        bool is_path = ctx->getCellDelay(usr.cell, usr.port, port.first, comb_delay);
+                        if (!is_path)
+                            continue;
+                        auto path_budget = net_data.at(port.second.net).min_remaining_budget;
+                        auto budget_share = budget_override ? 0 : path_budget / net_length_plus_one;
+                        usr.budget = std::min(usr.budget, net_delay + budget_share);
+                        net_min_remaining_budget = std::min(net_min_remaining_budget, path_budget - budget_share);
+                    }
                 }
             }
         }
-        return value;
-    }
 
-    delay_t walk_paths()
-    {
-        delay_t default_slack = delay_t(1.0e12 / ctx->target_freq);
+        if (crit_path) {
+            // Walk backwards from the most critical net
+            while (crit_net) {
+                const PortInfo *crit_ipin = nullptr;
+                delay_t max_arrival = std::numeric_limits<delay_t>::min();
 
-        // Go through all clocked drivers and distribute the available path
-        //   slack evenly into the budget of every sink on the path
-        for (auto &cell : ctx->cells) {
-            for (auto port : cell.second->ports) {
-                if (port.second.type == PORT_OUT) {
-                    IdString clock_domain = ctx->getPortClock(cell.second.get(), port.first);
-                    if (clock_domain != IdString()) {
-                        delay_t slack = default_slack; // TODO: clock constraints
-                        DelayInfo clkToQ;
-                        if (ctx->getCellDelay(cell.second.get(), clock_domain, port.first, clkToQ))
-                            slack -= clkToQ.maxDelay();
-                        if (port.second.net)
-                            follow_net(port.second.net, 0, slack);
+                // Look at all input ports on its driving cell
+                for (const auto &port : crit_net->driver.cell->ports) {
+                    if (port.second.type != PORT_IN || !port.second.net)
+                        continue;
+                    DelayInfo comb_delay;
+                    bool is_path =
+                            ctx->getCellDelay(crit_net->driver.cell, port.first, crit_net->driver.port, comb_delay);
+                    if (!is_path)
+                        continue;
+                    // If input port is influenced by a clock, skip
+                    IdString portClock;
+                    TimingPortClass portClass = ctx->getPortTimingClass(crit_net->driver.cell, port.first, portClock);
+                    if (portClass == TMG_REGISTER_INPUT || portClass == TMG_CLOCK_INPUT || portClass == TMG_ENDPOINT ||
+                        portClass == TMG_IGNORE)
+                        continue;
+
+                    // And find the fanin net with the latest arrival time
+                    const auto net_arrival = net_data.at(port.second.net).max_arrival;
+                    if (net_arrival > max_arrival) {
+                        max_arrival = net_arrival;
+                        crit_ipin = &port.second;
                     }
                 }
+
+                if (!crit_ipin)
+                    break;
+
+                // Now convert PortInfo* into a PortRef*
+                for (auto &usr : crit_ipin->net->users) {
+                    if (usr.cell->name == crit_net->driver.cell->name && usr.port == crit_ipin->name) {
+                        crit_path->push_back(&usr);
+                        break;
+                    }
+                }
+                crit_net = crit_ipin->net;
             }
+            std::reverse(crit_path->begin(), crit_path->end());
         }
         return min_slack;
     }
@@ -141,10 +303,9 @@ struct Timing
     void assign_budget()
     {
         // Clear delays to a very high value first
-        delay_t default_slack = delay_t(1.0e12 / ctx->target_freq);
         for (auto &net : ctx->nets) {
             for (auto &usr : net.second->users) {
-                usr.budget = default_slack;
+                usr.budget = std::numeric_limits<delay_t>::max();
             }
         }
 
@@ -180,16 +341,15 @@ void assign_budget(Context *ctx, bool quiet)
         }
     }
 
-    // For slack redistribution, if user has not specified a frequency
-    //   dynamically adjust the target frequency to be the currently
-    //   achieved maximum
+    // For slack redistribution, if user has not specified a frequency dynamically adjust the target frequency to be the
+    // currently achieved maximum
     if (ctx->auto_freq && ctx->slack_redist_iter > 0) {
-        delay_t default_slack = delay_t(1.0e12 / ctx->target_freq);
-        ctx->target_freq = 1e12 / (default_slack - timing.min_slack);
+        delay_t default_slack = delay_t((1.0e9 / ctx->getDelayNS(1)) / ctx->target_freq);
+        ctx->target_freq = 1.0e9 / ctx->getDelayNS(default_slack - timing.min_slack);
         if (ctx->verbose)
-            log_info("minimum slack for this assign = %d, target Fmax for next "
+            log_info("minimum slack for this assign = %.2f ns, target Fmax for next "
                      "update = %.2f MHz\n",
-                     timing.min_slack, ctx->target_freq / 1e6);
+                     ctx->getDelayNS(timing.min_slack), ctx->target_freq / 1e6);
     }
 
     if (!quiet)
@@ -217,7 +377,9 @@ void timing_analysis(Context *ctx, bool print_histogram, bool print_path)
             auto &front = crit_path.front();
             auto &front_port = front->cell->ports.at(front->port);
             auto &front_driver = front_port.net->driver;
-            auto last_port = ctx->getPortClock(front_driver.cell, front_driver.port);
+
+            IdString last_port;
+            ctx->getPortTimingClass(front_driver.cell, front_driver.port, last_port);
             for (auto sink : crit_path) {
                 auto sink_cell = sink->cell;
                 auto &port = sink_cell->ports.at(sink->port);
@@ -227,14 +389,15 @@ void timing_analysis(Context *ctx, bool print_histogram, bool print_path)
                 DelayInfo comb_delay;
                 ctx->getCellDelay(sink_cell, last_port, driver.port, comb_delay);
                 total += comb_delay.maxDelay();
-                log_info("%4d %4d  Source %s.%s\n", comb_delay.maxDelay(), total, driver_cell->name.c_str(ctx),
-                         driver.port.c_str(ctx));
+                log_info("%4.1f %4.1f  Source %s.%s\n", ctx->getDelayNS(comb_delay.maxDelay()), ctx->getDelayNS(total),
+                         driver_cell->name.c_str(ctx), driver.port.c_str(ctx));
                 auto net_delay = ctx->getNetinfoRouteDelay(net, *sink);
                 total += net_delay;
                 auto driver_loc = ctx->getBelLocation(driver_cell->bel);
                 auto sink_loc = ctx->getBelLocation(sink_cell->bel);
-                log_info("%4d %4d    Net %s budget %d (%d,%d) -> (%d,%d)\n", net_delay, total, net->name.c_str(ctx),
-                         sink->budget, driver_loc.x, driver_loc.y, sink_loc.x, sink_loc.y);
+                log_info("%4.1f %4.1f    Net %s budget %f ns (%d,%d) -> (%d,%d)\n", ctx->getDelayNS(net_delay),
+                         ctx->getDelayNS(total), net->name.c_str(ctx), ctx->getDelayNS(sink->budget), driver_loc.x,
+                         driver_loc.y, sink_loc.x, sink_loc.y);
                 log_info("                Sink %s.%s\n", sink_cell->name.c_str(ctx), sink->port.c_str(ctx));
                 last_port = sink->port;
             }
@@ -242,8 +405,8 @@ void timing_analysis(Context *ctx, bool print_histogram, bool print_path)
         }
     }
 
-    delay_t default_slack = delay_t(1.0e12 / ctx->target_freq);
-    log_info("estimated Fmax = %.2f MHz\n", 1e6 / (default_slack - min_slack));
+    delay_t default_slack = delay_t((1.0e9 / ctx->getDelayNS(1)) / ctx->target_freq);
+    log_info("estimated Fmax = %.2f MHz\n", 1e3 / ctx->getDelayNS(default_slack - min_slack));
 
     if (print_histogram && slack_histogram.size() > 0) {
         constexpr unsigned num_bins = 20;
diff --git a/docs/archapi.md b/docs/archapi.md
index 1ead4c62..df2bc468 100644
--- a/docs/archapi.md
+++ b/docs/archapi.md
@@ -431,13 +431,11 @@ Cell Delay Methods
 Returns the delay for the specified path through a cell in the `&delay` argument. The method returns
 false if there is no timing relationship from `fromPort` to `toPort`.
 
-### IdString getPortClock(const CellInfo \*cell, IdString port) const
+### TimingPortClass getPortTimingClass(const CellInfo *cell, IdString port, IdString &clockPort) const
 
-Returns the clock input port for the specified output port.
-
-### bool isClockPort(const CellInfo \*cell, IdString port) const
-
-Returns true if the specified port is a clock input.
+Return the _timing port class_ of a port. This can be a register or combinational input or output; clock input or
+output; general startpoint or endpoint; or a port ignored for timing purposes. For register ports, clockPort is set
+to the associated clock port.
 
 Placer Methods
 --------------
diff --git a/ecp5/arch.cc b/ecp5/arch.cc
index 23db8ae5..4358fdaf 100644
--- a/ecp5/arch.cc
+++ b/ecp5/arch.cc
@@ -330,7 +330,6 @@ BelId Arch::getPioByFunctionName(const std::string &name) const
 }
 
 std::vector<IdString> Arch::getBelPins(BelId bel) const
-
 {
     std::vector<IdString> ret;
     NPNR_ASSERT(bel != BelId());
@@ -454,9 +453,10 @@ bool Arch::getCellDelay(const CellInfo *cell, IdString fromPort, IdString toPort
     return false;
 }
 
-IdString Arch::getPortClock(const CellInfo *cell, IdString port) const { return IdString(); }
-
-bool Arch::isClockPort(const CellInfo *cell, IdString port) const { return false; }
+TimingPortClass Arch::getPortTimingClass(const CellInfo *cell, IdString port, IdString &clockPort) const
+{
+    return TMG_IGNORE;
+}
 
 std::vector<std::pair<std::string, std::string>> Arch::getTilesAtLocation(int row, int col)
 {
diff --git a/ecp5/arch.h b/ecp5/arch.h
index b6cc313f..3e2f203b 100644
--- a/ecp5/arch.h
+++ b/ecp5/arch.h
@@ -414,6 +414,7 @@ struct Arch : BaseCtx
     std::string getChipName() const;
 
     IdString archId() const { return id("ecp5"); }
+    ArchArgs archArgs() const { return args; }
     IdString archArgsToId(ArchArgs args) const;
 
     // -------------------------------------------------
@@ -824,10 +825,8 @@ struct Arch : BaseCtx
     // Get the delay through a cell from one port to another, returning false
     // if no path exists
     bool getCellDelay(const CellInfo *cell, IdString fromPort, IdString toPort, DelayInfo &delay) const;
-    // Get the associated clock to a port, or empty if the port is combinational
-    IdString getPortClock(const CellInfo *cell, IdString port) const;
-    // Return true if a port is a clock
-    bool isClockPort(const CellInfo *cell, IdString port) const;
+    // Get the port class, also setting clockPort if applicable
+    TimingPortClass getPortTimingClass(const CellInfo *cell, IdString port, IdString &clockPort) const;
     // Return true if a port is a net
     bool isGlobalNet(const NetInfo *net) const;
 
diff --git a/ecp5/main.cc b/ecp5/main.cc
index ecbe747d..5ad5a9bf 100644
--- a/ecp5/main.cc
+++ b/ecp5/main.cc
@@ -19,191 +19,84 @@
 
 #ifdef MAIN_EXECUTABLE
 
-#ifndef NO_GUI
-#include <QApplication>
-#include "application.h"
-#include "mainwindow.h"
-#endif
-#ifndef NO_PYTHON
-#include "pybindings.h"
-#endif
-#include <boost/filesystem/convenience.hpp>
-#include <boost/program_options.hpp>
 #include <fstream>
-#include <iostream>
-
-#include "log.h"
-#include "nextpnr.h"
-#include "version.h"
-
 #include "bitstream.h"
+#include "command.h"
 #include "design_utils.h"
-#include "jsonparse.h"
+#include "log.h"
 #include "timing.h"
 
 USING_NEXTPNR_NAMESPACE
 
-int main(int argc, char *argv[])
+class ECP5CommandHandler : public CommandHandler
 {
-    try {
-
-        namespace po = boost::program_options;
-        int rc = 0;
-
-        log_files.push_back(stdout);
-
-        po::options_description options("Allowed options");
-        options.add_options()("help,h", "show help");
-        options.add_options()("verbose,v", "verbose output");
-        options.add_options()("force,f", "keep running after errors");
-#ifndef NO_GUI
-        options.add_options()("gui", "start gui");
-#endif
-        options.add_options()("test", "check architecture database integrity");
-
-        options.add_options()("25k", "set device type to LFE5U-25F");
-        options.add_options()("45k", "set device type to LFE5U-45F");
-        options.add_options()("85k", "set device type to LFE5U-85F");
-
-        options.add_options()("package", po::value<std::string>(), "select device package (defaults to CABGA381)");
-
-        options.add_options()("json", po::value<std::string>(), "JSON design file to ingest");
-        options.add_options()("seed", po::value<int>(), "seed value for random number generator");
-
-        options.add_options()("basecfg", po::value<std::string>(), "base chip configuration in Trellis text format");
-        options.add_options()("textcfg", po::value<std::string>(), "textual configuration in Trellis format to write");
-
-        po::positional_options_description pos;
-#ifndef NO_PYTHON
-        options.add_options()("run", po::value<std::vector<std::string>>(), "python file to execute");
-        pos.add("run", -1);
-#endif
-        options.add_options()("version,V", "show version");
-
-        po::variables_map vm;
-        try {
-            po::parsed_options parsed = po::command_line_parser(argc, argv).options(options).positional(pos).run();
-
-            po::store(parsed, vm);
-
-            po::notify(vm);
-        }
-
-        catch (std::exception &e) {
-            std::cout << e.what() << "\n";
-            return 1;
-        }
-
-        if (vm.count("help") || argc == 1) {
-            std::cout << boost::filesystem::basename(argv[0])
-                      << " -- Next Generation Place and Route (git "
-                         "sha1 " GIT_COMMIT_HASH_STR ")\n";
-            std::cout << "\n";
-            std::cout << options << "\n";
-            return argc != 1;
-        }
+  public:
+    ECP5CommandHandler(int argc, char **argv);
+    virtual ~ECP5CommandHandler(){};
+    std::unique_ptr<Context> createContext() override;
+    void setupArchContext(Context *ctx) override{};
+    void validate() override;
+    void customBitstream(Context *ctx) override;
 
-        if (vm.count("version")) {
-            std::cout << boost::filesystem::basename(argv[0])
-                      << " -- Next Generation Place and Route (git "
-                         "sha1 " GIT_COMMIT_HASH_STR ")\n";
-            return 1;
-        }
+  protected:
+    po::options_description getArchOptions();
+};
 
-        ArchArgs args;
-        args.type = ArchArgs::LFE5U_45F;
+ECP5CommandHandler::ECP5CommandHandler(int argc, char **argv) : CommandHandler(argc, argv) {}
 
-        if (vm.count("25k"))
-            args.type = ArchArgs::LFE5U_25F;
-        if (vm.count("45k"))
-            args.type = ArchArgs::LFE5U_45F;
-        if (vm.count("85k"))
-            args.type = ArchArgs::LFE5U_85F;
-        if (vm.count("package"))
-            args.package = vm["package"].as<std::string>();
-        else
-            args.package = "CABGA381";
-        args.speed = 6;
-        std::unique_ptr<Context> ctx = std::unique_ptr<Context>(new Context(args));
-
-        if (vm.count("verbose")) {
-            ctx->verbose = true;
-        }
-
-        if (vm.count("force")) {
-            ctx->force = true;
-        }
-
-        if (vm.count("seed")) {
-            ctx->rngseed(vm["seed"].as<int>());
-        }
-
-        ctx->timing_driven = true;
-        if (vm.count("no-tmdriv"))
-            ctx->timing_driven = false;
-
-        if (vm.count("test"))
-            ctx->archcheck();
-
-#ifndef NO_GUI
-        if (vm.count("gui")) {
-            Application a(argc, argv);
-            MainWindow w(std::move(ctx), args);
-            w.show();
-
-            return a.exec();
-        }
-#endif
-        if (vm.count("json")) {
-            std::string filename = vm["json"].as<std::string>();
-            std::ifstream f(filename);
-            if (!parse_json_file(f, filename, ctx.get()))
-                log_error("Loading design failed.\n");
-
-            if (!ctx->pack() && !ctx->force)
-                log_error("Packing design failed.\n");
-            if (vm.count("freq"))
-                ctx->target_freq = vm["freq"].as<double>() * 1e6;
-            assign_budget(ctx.get());
-            ctx->check();
-            print_utilisation(ctx.get());
-
-            if (!ctx->place() && !ctx->force)
-                log_error("Placing design failed.\n");
-            ctx->check();
-            if (!ctx->route() && !ctx->force)
-                log_error("Routing design failed.\n");
+po::options_description ECP5CommandHandler::getArchOptions()
+{
+    po::options_description specific("Architecture specific options");
+    specific.add_options()("25k", "set device type to LFE5U-25F");
+    specific.add_options()("45k", "set device type to LFE5U-45F");
+    specific.add_options()("85k", "set device type to LFE5U-85F");
+    specific.add_options()("package", po::value<std::string>(), "select device package (defaults to CABGA381)");
+    specific.add_options()("basecfg", po::value<std::string>(), "base chip configuration in Trellis text format");
+    specific.add_options()("textcfg", po::value<std::string>(), "textual configuration in Trellis format to write");
+    return specific;
+}
+void ECP5CommandHandler::validate()
+{
+    if ((vm.count("25k") + vm.count("45k") + vm.count("85k")) > 1)
+        log_error("Only one device type can be set\n");
+}
 
-            std::string basecfg;
-            if (vm.count("basecfg"))
-                basecfg = vm["basecfg"].as<std::string>();
+void ECP5CommandHandler::customBitstream(Context *ctx)
+{
+    std::string basecfg;
+    if (vm.count("basecfg"))
+        basecfg = vm["basecfg"].as<std::string>();
 
-            std::string textcfg;
-            if (vm.count("textcfg"))
-                textcfg = vm["textcfg"].as<std::string>();
-            write_bitstream(ctx.get(), basecfg, textcfg);
-        }
+    std::string textcfg;
+    if (vm.count("textcfg"))
+        textcfg = vm["textcfg"].as<std::string>();
 
-#ifndef NO_PYTHON
-        if (vm.count("run")) {
-            init_python(argv[0], true);
-            python_export_global("ctx", ctx);
+    write_bitstream(ctx, basecfg, textcfg);
+}
 
-            std::vector<std::string> files = vm["run"].as<std::vector<std::string>>();
-            for (auto filename : files)
-                execute_python_file(filename.c_str());
+std::unique_ptr<Context> ECP5CommandHandler::createContext()
+{
+    chipArgs.type = ArchArgs::LFE5U_45F;
+
+    if (vm.count("25k"))
+        chipArgs.type = ArchArgs::LFE5U_25F;
+    if (vm.count("45k"))
+        chipArgs.type = ArchArgs::LFE5U_45F;
+    if (vm.count("85k"))
+        chipArgs.type = ArchArgs::LFE5U_85F;
+    if (vm.count("package"))
+        chipArgs.package = vm["package"].as<std::string>();
+    else
+        chipArgs.package = "CABGA381";
+    chipArgs.speed = 6;
+
+    return std::unique_ptr<Context>(new Context(chipArgs));
+}
 
-            deinit_python();
-        }
-#endif
-        return rc;
-    } catch (log_execution_error_exception) {
-#if defined(_MSC_VER)
-        _exit(EXIT_FAILURE);
-#else
-        _Exit(EXIT_FAILURE);
-#endif
-    }
+int main(int argc, char *argv[])
+{
+    ECP5CommandHandler handler(argc, argv);
+    return handler.exec();
 }
 
 #endif
diff --git a/ecp5/project.cc b/ecp5/project.cc
new file mode 100644
index 00000000..6c1f6a94
--- /dev/null
+++ b/ecp5/project.cc
@@ -0,0 +1,55 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Miodrag Milanovic <miodrag@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 "project.h"
+#include <boost/filesystem/convenience.hpp>
+#include <boost/property_tree/json_parser.hpp>
+#include <fstream>
+#include "log.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+void ProjectHandler::saveArch(Context *ctx, pt::ptree &root)
+{
+    root.put("project.arch.package", ctx->archArgs().package);
+    root.put("project.arch.speed", ctx->archArgs().speed);
+}
+
+std::unique_ptr<Context> ProjectHandler::createContext(pt::ptree &root)
+{
+    ArchArgs chipArgs;
+    std::string arch_type = root.get<std::string>("project.arch.type");
+    if (arch_type == "25k") {
+        chipArgs.type = ArchArgs::LFE5U_25F;
+    }
+    if (arch_type == "45k") {
+        chipArgs.type = ArchArgs::LFE5U_45F;
+    }
+    if (arch_type == "85k") {
+        chipArgs.type = ArchArgs::LFE5U_85F;
+    }
+    chipArgs.package = root.get<std::string>("project.arch.package");
+    chipArgs.speed = root.get<int>("project.arch.speed");
+
+    return std::unique_ptr<Context>(new Context(chipArgs));
+}
+
+void ProjectHandler::loadArch(Context *ctx, pt::ptree &root, std::string path) {}
+
+NEXTPNR_NAMESPACE_END
diff --git a/generic/arch.cc b/generic/arch.cc
index a6d41e1e..4e25b2c8 100644
--- a/generic/arch.cc
+++ b/generic/arch.cc
@@ -175,7 +175,7 @@ void Arch::setGroupDecal(GroupId group, DecalXY decalxy)
 
 // ---------------------------------------------------------------
 
-Arch::Arch(ArchArgs) : chipName("generic") {}
+Arch::Arch(ArchArgs args) : chipName("generic"), args(args) {}
 
 void IdString::initialize_arch(const BaseCtx *ctx) {}
 
@@ -435,9 +435,11 @@ bool Arch::getCellDelay(const CellInfo *cell, IdString fromPort, IdString toPort
     return false;
 }
 
-IdString Arch::getPortClock(const CellInfo *cell, IdString port) const { return IdString(); }
-
-bool Arch::isClockPort(const CellInfo *cell, IdString port) const { return false; }
+// Get the port class, also setting clockPort if applicable
+TimingPortClass Arch::getPortTimingClass(const CellInfo *cell, IdString port, IdString &clockPort) const
+{
+    return TMG_IGNORE;
+}
 
 bool Arch::isValidBelForCell(CellInfo *cell, BelId bel) const { return true; }
 bool Arch::isBelLocationValid(BelId bel) const { return true; }
diff --git a/generic/arch.h b/generic/arch.h
index b38d5916..ee7d0403 100644
--- a/generic/arch.h
+++ b/generic/arch.h
@@ -121,11 +121,13 @@ struct Arch : BaseCtx
     // ---------------------------------------------------------------
     // Common Arch API. Every arch must provide the following methods.
 
+    ArchArgs args;
     Arch(ArchArgs args);
 
     std::string getChipName() const { return chipName; }
 
     IdString archId() const { return id("generic"); }
+    ArchArgs archArgs() const { return args; }
     IdString archArgsToId(ArchArgs args) const { return id("none"); }
 
     int getGridDimX() const { return gridDimX; }
@@ -207,8 +209,8 @@ struct Arch : BaseCtx
     DecalXY getGroupDecal(GroupId group) const;
 
     bool getCellDelay(const CellInfo *cell, IdString fromPort, IdString toPort, DelayInfo &delay) const;
-    IdString getPortClock(const CellInfo *cell, IdString port) const;
-    bool isClockPort(const CellInfo *cell, IdString port) const;
+    // Get the port class, also setting clockPort if applicable
+    TimingPortClass getPortTimingClass(const CellInfo *cell, IdString port, IdString &clockPort) const;
 
     bool isValidBelForCell(CellInfo *cell, BelId bel) const;
     bool isBelLocationValid(BelId bel) const;
diff --git a/generic/main.cc b/generic/main.cc
index 8653da01..412a28ac 100644
--- a/generic/main.cc
+++ b/generic/main.cc
@@ -19,123 +19,47 @@
 
 #ifdef MAIN_EXECUTABLE
 
-#ifndef NO_GUI
-#include <QApplication>
-#include "application.h"
-#include "mainwindow.h"
-#endif
-#ifndef NO_PYTHON
-#include "pybindings.h"
-#endif
-#include <boost/filesystem/convenience.hpp>
-#include <boost/program_options.hpp>
-#include <iostream>
+#include <fstream>
+#include "command.h"
+#include "design_utils.h"
 #include "log.h"
-#include "nextpnr.h"
-#include "version.h"
+#include "timing.h"
 
 USING_NEXTPNR_NAMESPACE
 
-int main(int argc, char *argv[])
+class GenericCommandHandler : public CommandHandler
 {
-    try {
-
-        namespace po = boost::program_options;
-        int rc = 0;
-
-        log_files.push_back(stdout);
-
-        po::options_description options("Allowed options");
-        options.add_options()("help,h", "show help");
-        options.add_options()("verbose,v", "verbose output");
-        options.add_options()("force,f", "keep running after errors");
-#ifndef NO_GUI
-        options.add_options()("gui", "start gui");
-#endif
-
-        po::positional_options_description pos;
-#ifndef NO_PYTHON
-        options.add_options()("run", po::value<std::vector<std::string>>(), "python file to execute");
-        pos.add("run", -1);
-#endif
-        options.add_options()("version,V", "show version");
-
-        po::variables_map vm;
-        try {
-            po::parsed_options parsed = po::command_line_parser(argc, argv).options(options).positional(pos).run();
-
-            po::store(parsed, vm);
-
-            po::notify(vm);
-        }
-
-        catch (std::exception &e) {
-            std::cout << e.what() << "\n";
-            return 1;
-        }
-
-        if (vm.count("help") || argc == 1) {
-            std::cout << boost::filesystem::basename(argv[0])
-                      << " -- Next Generation Place and Route (git "
-                         "sha1 " GIT_COMMIT_HASH_STR ")\n";
-            std::cout << "\n";
-            std::cout << options << "\n";
-            return argc != 1;
-        }
+  public:
+    GenericCommandHandler(int argc, char **argv);
+    virtual ~GenericCommandHandler(){};
+    std::unique_ptr<Context> createContext() override;
+    void setupArchContext(Context *ctx) override{};
+    void customBitstream(Context *ctx) override;
 
-        if (vm.count("version")) {
-            std::cout << boost::filesystem::basename(argv[0])
-                      << " -- Next Generation Place and Route (git "
-                         "sha1 " GIT_COMMIT_HASH_STR ")\n";
-            return 1;
-        }
+  protected:
+    po::options_description getArchOptions();
+};
 
-        ArchArgs chipArgs{};
-        std::unique_ptr<Context> ctx = std::unique_ptr<Context>(new Context(chipArgs));
+GenericCommandHandler::GenericCommandHandler(int argc, char **argv) : CommandHandler(argc, argv) {}
 
-        if (vm.count("verbose")) {
-            ctx->verbose = true;
-        }
-
-        if (vm.count("force")) {
-            ctx->force = true;
-        }
-
-        if (vm.count("seed")) {
-            ctx->rngseed(vm["seed"].as<int>());
-        }
-
-#ifndef NO_GUI
-        if (vm.count("gui")) {
-            Application a(argc, argv);
-            MainWindow w(std::move(ctx), chipArgs);
-            w.show();
-
-            return a.exec();
-        }
-#endif
-
-#ifndef NO_PYTHON
-        if (vm.count("run")) {
-            init_python(argv[0], true);
-            python_export_global("ctx", *ctx.get());
+po::options_description GenericCommandHandler::getArchOptions()
+{
+    po::options_description specific("Architecture specific options");
+    specific.add_options()("generic", "set device type to generic");
+    return specific;
+}
 
-            std::vector<std::string> files = vm["run"].as<std::vector<std::string>>();
-            for (auto filename : files)
-                execute_python_file(filename.c_str());
+void GenericCommandHandler::customBitstream(Context *ctx) { log_error("Here is when bitstream gets created"); }
 
-            deinit_python();
-        }
-#endif
+std::unique_ptr<Context> GenericCommandHandler::createContext()
+{
+    return std::unique_ptr<Context>(new Context(chipArgs));
+}
 
-        return rc;
-    } catch (log_execution_error_exception) {
-#if defined(_MSC_VER)
-        _exit(EXIT_FAILURE);
-#else
-        _Exit(EXIT_FAILURE);
-#endif
-    }
+int main(int argc, char *argv[])
+{
+    GenericCommandHandler handler(argc, argv);
+    return handler.exec();
 }
 
 #endif
diff --git a/generic/project.cc b/generic/project.cc
new file mode 100644
index 00000000..8103e91f
--- /dev/null
+++ b/generic/project.cc
@@ -0,0 +1,37 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Miodrag Milanovic <miodrag@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 "project.h"
+#include <boost/filesystem/convenience.hpp>
+#include <fstream>
+#include "log.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+void ProjectHandler::saveArch(Context *ctx, pt::ptree &root) {}
+
+std::unique_ptr<Context> ProjectHandler::createContext(pt::ptree &root)
+{
+    ArchArgs chipArgs;
+    return std::unique_ptr<Context>(new Context(chipArgs));
+}
+
+void ProjectHandler::loadArch(Context *ctx, pt::ptree &root, std::string path) {}
+
+NEXTPNR_NAMESPACE_END
diff --git a/gui/basewindow.cc b/gui/basewindow.cc
index 53720156..857919ea 100644
--- a/gui/basewindow.cc
+++ b/gui/basewindow.cc
@@ -31,6 +31,7 @@
 #include "jsonparse.h"

 #include "log.h"

 #include "mainwindow.h"

+#include "project.h"

 #include "pythontab.h"

 

 static void initBasenameResource() { Q_INIT_RESOURCE(base); }

@@ -302,8 +303,7 @@ void BaseMainWindow::load_json(std::string filename)
     if (parse_json_file(f, filename, ctx.get())) {

         log("Loading design successful.\n");

         Q_EMIT updateTreeView();

-        actionPack->setEnabled(true);

-        onJsonLoaded();

+        updateJsonLoaded();

     } else {

         actionLoadJSON->setEnabled(true);

         log("Loading design failed.\n");

@@ -425,4 +425,42 @@ void BaseMainWindow::disableActions()
     onDisableActions();

 }

 

+void BaseMainWindow::updateJsonLoaded()

+{

+    disableActions();

+    actionPack->setEnabled(true);

+    onJsonLoaded();

+}

+

+void BaseMainWindow::open_proj()

+{

+    QString fileName = QFileDialog::getOpenFileName(this, QString("Open Project"), QString(), QString("*.proj"));

+    if (!fileName.isEmpty()) {

+        try {

+            ProjectHandler proj;

+            disableActions();

+            ctx = proj.load(fileName.toStdString());

+            Q_EMIT contextChanged(ctx.get());

+            log_info("Loaded project %s...\n", fileName.toStdString().c_str());

+            updateJsonLoaded();

+            onProjectLoaded();

+        } catch (log_execution_error_exception) {

+        }

+    }

+}

+

+void BaseMainWindow::save_proj()

+{

+    if (currentProj.empty()) {

+        QString fileName = QFileDialog::getSaveFileName(this, QString("Save Project"), QString(), QString("*.proj"));

+        if (fileName.isEmpty())

+            return;

+        currentProj = fileName.toStdString();

+    }

+    if (!currentProj.empty()) {

+        ProjectHandler proj;

+        proj.save(ctx.get(), currentProj);

+    }

+}

+

 NEXTPNR_NAMESPACE_END

diff --git a/gui/basewindow.h b/gui/basewindow.h
index 341cc8e2..6e8f8587 100644
--- a/gui/basewindow.h
+++ b/gui/basewindow.h
@@ -48,14 +48,16 @@ class BaseMainWindow : public QMainWindow
     explicit BaseMainWindow(std::unique_ptr<Context> context, ArchArgs args, QWidget *parent = 0);

     virtual ~BaseMainWindow();

     Context *getContext() { return ctx.get(); }

-

-    void load_json(std::string filename);

+    void updateJsonLoaded();

 

   protected:

     void createMenusAndBars();

     void disableActions();

+    void load_json(std::string filename);

+

     virtual void onDisableActions(){};

     virtual void onJsonLoaded(){};

+    virtual void onProjectLoaded(){};

     virtual void onPackFinished(){};

     virtual void onBudgetFinished(){};

     virtual void onPlaceFinished(){};

@@ -66,8 +68,9 @@ class BaseMainWindow : public QMainWindow
     void closeTab(int index);

 

     virtual void new_proj() = 0;

-    virtual void open_proj() = 0;

-    virtual bool save_proj() = 0;

+

+    void open_proj();

+    void save_proj();

 

     void open_json();

     void budget();

@@ -93,6 +96,7 @@ class BaseMainWindow : public QMainWindow
     TaskManager *task;

     bool timing_driven;

     std::string currentJson;

+    std::string currentProj;

 

     // main widgets

     QTabWidget *tabWidget;

diff --git a/gui/ecp5/mainwindow.cc b/gui/ecp5/mainwindow.cc
index efaad364..4fc8be16 100644
--- a/gui/ecp5/mainwindow.cc
+++ b/gui/ecp5/mainwindow.cc
@@ -29,7 +29,8 @@ static void initMainResource() { Q_INIT_RESOURCE(nextpnr); }
 

 NEXTPNR_NAMESPACE_BEGIN

 

-MainWindow::MainWindow(std::unique_ptr<Context> context, ArchArgs args, QWidget *parent) : BaseMainWindow(std::move(context), args, parent)

+MainWindow::MainWindow(std::unique_ptr<Context> context, ArchArgs args, QWidget *parent)

+        : BaseMainWindow(std::move(context), args, parent)

 {

     initMainResource();

 

@@ -50,7 +51,8 @@ void MainWindow::newContext(Context *ctx)
     setWindowTitle(title.c_str());

 }

 

-void MainWindow::createMenu() {

+void MainWindow::createMenu()

+{

     // Add arch specific actions

     actionLoadBase = new QAction("Open Base Config", this);

     actionLoadBase->setIcon(QIcon(":/icons/resources/open_base.png"));

@@ -71,7 +73,7 @@ void MainWindow::createMenu() {
 

     menuDesign->addSeparator();

     menuDesign->addAction(actionLoadBase);

-    menuDesign->addAction(actionSaveConfig);    

+    menuDesign->addAction(actionSaveConfig);

 }

 

 static const ChipInfoPOD *get_chip_info(const RelPtr<ChipInfoPOD> *ptr) { return ptr->get(); }

@@ -96,8 +98,8 @@ static QStringList getSupportedPackages(ArchArgs::ArchArgsTypes chip)
     return packages;

 }

 

-

-void MainWindow::new_proj() {

+void MainWindow::new_proj()

+{

     QMap<QString, int> arch;

     arch.insert("Lattice ECP5 25K", ArchArgs::LFE5U_25F);

     arch.insert("Lattice ECP5 45K", ArchArgs::LFE5U_45F);

@@ -124,10 +126,6 @@ void MainWindow::new_proj() {
     }

 }

 

-void MainWindow::open_proj() {}

-

-bool MainWindow::save_proj() { return false; }

-

 void MainWindow::load_base_config(std::string filename)

 {

     disableActions();

diff --git a/gui/ecp5/mainwindow.h b/gui/ecp5/mainwindow.h
index d1d5a5a2..aa1af17b 100644
--- a/gui/ecp5/mainwindow.h
+++ b/gui/ecp5/mainwindow.h
@@ -42,11 +42,10 @@ class MainWindow : public BaseMainWindow
 

   protected Q_SLOTS:

     virtual void new_proj();

-    virtual void open_proj();

-    virtual bool save_proj();

     void newContext(Context *ctx);

     void open_base();

     void save_config();

+

   private:

     QAction *actionLoadBase;

     QAction *actionSaveConfig;

diff --git a/gui/generic/mainwindow.cc b/gui/generic/mainwindow.cc
index 050c0fb8..76837ed4 100644
--- a/gui/generic/mainwindow.cc
+++ b/gui/generic/mainwindow.cc
@@ -23,7 +23,8 @@ static void initMainResource() { Q_INIT_RESOURCE(nextpnr); }
 

 NEXTPNR_NAMESPACE_BEGIN

 

-MainWindow::MainWindow(std::unique_ptr<Context> context, ArchArgs args, QWidget *parent) : BaseMainWindow(std::move(context), args, parent)

+MainWindow::MainWindow(std::unique_ptr<Context> context, ArchArgs args, QWidget *parent)

+        : BaseMainWindow(std::move(context), args, parent)

 {

     initMainResource();

 

@@ -48,8 +49,4 @@ void MainWindow::createMenu() {}
 

 void MainWindow::new_proj() {}

 

-void MainWindow::open_proj() {}

-

-bool MainWindow::save_proj() { return false; }

-

 NEXTPNR_NAMESPACE_END

diff --git a/gui/generic/mainwindow.h b/gui/generic/mainwindow.h
index 375436b6..a4ce9958 100644
--- a/gui/generic/mainwindow.h
+++ b/gui/generic/mainwindow.h
@@ -37,8 +37,6 @@ class MainWindow : public BaseMainWindow
 

   protected Q_SLOTS:

     virtual void new_proj();

-    virtual void open_proj();

-    virtual bool save_proj();

     void newContext(Context *ctx);

 };

 

diff --git a/gui/ice40/mainwindow.cc b/gui/ice40/mainwindow.cc
index 40b863e9..35ad5768 100644
--- a/gui/ice40/mainwindow.cc
+++ b/gui/ice40/mainwindow.cc
@@ -24,8 +24,7 @@
 #include <QIcon>

 #include <QInputDialog>

 #include <QLineEdit>

-#include <boost/property_tree/json_parser.hpp>

-#include <boost/property_tree/ptree.hpp>

+#include <fstream>

 #include "bitstream.h"

 #include "design_utils.h"

 #include "jsonparse.h"

@@ -166,86 +165,6 @@ void MainWindow::newContext(Context *ctx)
     setWindowTitle(title.c_str());

 }

 

-void MainWindow::open_proj()

-{

-    QMap<std::string, int> arch;

-#ifdef ICE40_HX1K_ONLY

-    arch.insert("hx1k", ArchArgs::HX1K);

-#else

-    arch.insert("lp384", ArchArgs::LP384);

-    arch.insert("lp1k", ArchArgs::LP1K);

-    arch.insert("hx1k", ArchArgs::HX1K);

-    arch.insert("up5k", ArchArgs::UP5K);

-    arch.insert("lp8k", ArchArgs::LP8K);

-    arch.insert("hx8k", ArchArgs::HX8K);

-#endif

-

-    QString fileName = QFileDialog::getOpenFileName(this, QString("Open Project"), QString(), QString("*.proj"));

-    if (!fileName.isEmpty()) {

-        try {

-            namespace pt = boost::property_tree;

-

-            std::string fn = fileName.toStdString();

-            currentProj = fn;

-            disableActions();

-

-            pt::ptree root;

-            std::string filename = fileName.toStdString();

-            pt::read_json(filename, root);

-            log_info("Loading project %s...\n", filename.c_str());

-            log_break();

-

-            int version = root.get<int>("project.version");

-            if (version != 1)

-                log_error("Wrong project format version.\n");

-

-            std::string arch_name = root.get<std::string>("project.arch.name");

-            if (arch_name != "ice40")

-                log_error("Unsuported project architecture.\n");

-

-            std::string arch_type = root.get<std::string>("project.arch.type");

-            std::string arch_package = root.get<std::string>("project.arch.package");

-

-            chipArgs.type = (ArchArgs::ArchArgsTypes)arch.value(arch_type);

-            chipArgs.package = arch_package;

-            ctx = std::unique_ptr<Context>(new Context(chipArgs));

-            Q_EMIT contextChanged(ctx.get());

-

-            QFileInfo fi(fileName);

-            QDir::setCurrent(fi.absoluteDir().absolutePath());

-            log_info("Setting current dir to %s...\n", fi.absoluteDir().absolutePath().toStdString().c_str());

-            log_info("Loading project %s...\n", filename.c_str());

-            log_info("Context changed to %s (%s)\n", arch_type.c_str(), arch_package.c_str());

-

-            auto project = root.get_child("project");

-            std::string json;

-            std::string pcf;

-            if (project.count("input")) {

-                auto input = project.get_child("input");

-                if (input.count("json"))

-                    json = input.get<std::string>("json");

-                if (input.count("pcf"))

-                    pcf = input.get<std::string>("pcf");

-            }

-

-            if (!(QFileInfo::exists(json.c_str()) && QFileInfo(json.c_str()).isFile())) {

-                log_error("Json file does not exist.\n");

-            }

-            if (!pcf.empty()) {

-                if (!(QFileInfo::exists(pcf.c_str()) && QFileInfo(pcf.c_str()).isFile())) {

-                    log_error("PCF file does not exist.\n");

-                }

-            }

-

-            log_info("Loading json: %s...\n", json.c_str());

-            load_json(json);

-            if (!pcf.empty())

-                load_pcf(json);

-        } catch (log_execution_error_exception) {

-        }

-    }

-}

-

 void MainWindow::open_pcf()

 {

     QString fileName = QFileDialog::getOpenFileName(this, QString("Open PCF"), QString(), QString("*.pcf"));

@@ -254,36 +173,6 @@ void MainWindow::open_pcf()
     }

 }

 

-bool MainWindow::save_proj()

-{

-    if (currentProj.empty()) {

-        QString fileName = QFileDialog::getSaveFileName(this, QString("Save Project"), QString(), QString("*.proj"));

-        if (fileName.isEmpty())

-            return false;

-        currentProj = fileName.toStdString();

-    }

-    if (!currentProj.empty()) {

-        namespace pt = boost::property_tree;

-        QFileInfo fi(currentProj.c_str());

-        QDir dir(fi.absoluteDir().absolutePath());

-        std::ofstream f(currentProj);

-        pt::ptree root;

-        root.put("project.version", 1);

-        root.put("project.name", fi.baseName().toStdString());

-        root.put("project.arch.name", ctx->archId().c_str(ctx.get()));

-        root.put("project.arch.type", ctx->archArgsToId(chipArgs).c_str(ctx.get()));

-        root.put("project.arch.package", chipArgs.package);

-        if (!currentJson.empty())

-            root.put("project.input.json", dir.relativeFilePath(currentJson.c_str()).toStdString());

-        if (!currentPCF.empty())

-            root.put("project.input.pcf", dir.relativeFilePath(currentPCF.c_str()).toStdString());

-        pt::write_json(f, root);

-        log_info("Project %s saved...\n", fi.baseName().toStdString().c_str());

-        return true;

-    }

-    return false;

-}

-

 void MainWindow::save_asc()

 {

     QString fileName = QFileDialog::getSaveFileName(this, QString("Save ASC"), QString(), QString("*.asc"));

@@ -304,5 +193,6 @@ void MainWindow::onDisableActions()
 

 void MainWindow::onJsonLoaded() { actionLoadPCF->setEnabled(true); }

 void MainWindow::onRouteFinished() { actionSaveAsc->setEnabled(true); }

+void MainWindow::onProjectLoaded() { actionLoadPCF->setEnabled(false); }

 

 NEXTPNR_NAMESPACE_END

diff --git a/gui/ice40/mainwindow.h b/gui/ice40/mainwindow.h
index 829375e2..201bf1b1 100644
--- a/gui/ice40/mainwindow.h
+++ b/gui/ice40/mainwindow.h
@@ -34,17 +34,17 @@ class MainWindow : public BaseMainWindow
 

   public:

     void createMenu();

-    void load_pcf(std::string filename);

 

   protected:

+    void load_pcf(std::string filename);

+

     void onDisableActions() override;

     void onJsonLoaded() override;

     void onRouteFinished() override;

+    void onProjectLoaded() override;

 

   protected Q_SLOTS:

     virtual void new_proj();

-    virtual void open_proj();

-    virtual bool save_proj();

 

     void open_pcf();

     void save_asc();

@@ -55,7 +55,6 @@ class MainWindow : public BaseMainWindow
     QAction *actionLoadPCF;

     QAction *actionSaveAsc;

 

-    std::string currentProj;

     std::string currentPCF;

 };

 

diff --git a/ice40/arch.cc b/ice40/arch.cc
index 0c078f0e..7e2dd7f7 100644
--- a/ice40/arch.cc
+++ b/ice40/arch.cc
@@ -27,6 +27,7 @@
 #include "placer1.h"
 #include "router1.h"
 #include "util.h"
+
 NEXTPNR_NAMESPACE_BEGIN
 
 // -----------------------------------------------------------------------
@@ -181,7 +182,8 @@ BelId Arch::getBelByLocation(Loc loc) const
 
 BelRange Arch::getBelsByTile(int x, int y) const
 {
-    // In iCE40 chipdb bels at the same tile are consecutive and dense z ordinates are used
+    // In iCE40 chipdb bels at the same tile are consecutive and dense z ordinates
+    // are used
     BelRange br;
 
     br.b.cursor = Arch::getBelByLocation(Loc(x, y, 0)).index;
@@ -535,23 +537,27 @@ bool Arch::getBudgetOverride(const NetInfo *net_info, const PortRef &sink, delay
         auto sink_loc = getBelLocation(sink.cell->bel);
         if (driver_loc.y == sink_loc.y)
             budget = 0;
-        else switch (args.type) {
+        else
+            switch (args.type) {
 #ifndef ICE40_HX1K_ONLY
             case ArchArgs::HX8K:
 #endif
             case ArchArgs::HX1K:
-                budget = 190; break;
+                budget = 190;
+                break;
 #ifndef ICE40_HX1K_ONLY
             case ArchArgs::LP384:
             case ArchArgs::LP1K:
             case ArchArgs::LP8K:
-                budget = 290; break;
+                budget = 290;
+                break;
             case ArchArgs::UP5K:
-                budget = 560; break;
+                budget = 560;
+                break;
 #endif
             default:
                 log_error("Unsupported iCE40 chip type.\n");
-        }
+            }
         return true;
     }
     return false;
@@ -770,27 +776,76 @@ bool Arch::getCellDelay(const CellInfo *cell, IdString fromPort, IdString toPort
     return false;
 }
 
-IdString Arch::getPortClock(const CellInfo *cell, IdString port) const
+// Get the port class, also setting clockPort to associated clock if applicable
+TimingPortClass Arch::getPortTimingClass(const CellInfo *cell, IdString port, IdString &clockPort) const
 {
-    if (cell->type == id_ICESTORM_LC && cell->lcInfo.dffEnable) {
-        if (port != id_LO && port != id_CIN && port != id_COUT)
-            return id_CLK;
+    if (cell->type == id_ICESTORM_LC) {
+        if (port == id_CLK)
+            return TMG_CLOCK_INPUT;
+        if (port == id_CIN)
+            return TMG_COMB_INPUT;
+        if (port == id_COUT || port == id_LO)
+            return TMG_COMB_OUTPUT;
+        if (cell->lcInfo.dffEnable) {
+            clockPort = id_CLK;
+            if (port == id_O)
+                return TMG_REGISTER_OUTPUT;
+            else
+                return TMG_REGISTER_INPUT;
+        } else {
+            if (port == id_O)
+                return TMG_COMB_OUTPUT;
+            else
+                return TMG_COMB_INPUT;
+        }
     } else if (cell->type == id_ICESTORM_RAM) {
+
+        if (port == id_RCLK || port == id_WCLK)
+            return TMG_CLOCK_INPUT;
+
         if (port.str(this)[0] == 'R')
-            return id_RCLK;
+            clockPort = id_RCLK;
         else
-            return id_WCLK;
-    }
-    return IdString();
-}
+            clockPort = id_WCLK;
 
-bool Arch::isClockPort(const CellInfo *cell, IdString port) const
-{
-    if (cell->type == id_ICESTORM_LC && port == id_CLK)
-        return true;
-    if (cell->type == id_ICESTORM_RAM && (port == id_RCLK || port == id_WCLK))
-        return true;
-    return false;
+        if (cell->ports.at(port).type == PORT_OUT)
+            return TMG_REGISTER_OUTPUT;
+        else
+            return TMG_REGISTER_INPUT;
+    } else if (cell->type == id_ICESTORM_DSP || cell->type == id_ICESTORM_SPRAM) {
+        clockPort = id_CLK;
+        if (port == id_CLK)
+            return TMG_CLOCK_INPUT;
+        else if (cell->ports.at(port).type == PORT_OUT)
+            return TMG_REGISTER_OUTPUT;
+        else
+            return TMG_REGISTER_INPUT;
+    } else if (cell->type == id_SB_IO) {
+        if (port == id_D_IN_0 || port == id_D_IN_1)
+            return TMG_STARTPOINT;
+        if (port == id_D_OUT_0 || port == id_D_OUT_1 || port == id_OUTPUT_ENABLE)
+            return TMG_ENDPOINT;
+        return TMG_IGNORE;
+    } else if (cell->type == id_ICESTORM_PLL) {
+        if (port == id_PLLOUT_A || port == id_PLLOUT_B)
+            return TMG_GEN_CLOCK;
+        return TMG_IGNORE;
+    } else if (cell->type == id_ICESTORM_LFOSC) {
+        if (port == id_CLKLF)
+            return TMG_GEN_CLOCK;
+        return TMG_IGNORE;
+    } else if (cell->type == id_ICESTORM_HFOSC) {
+        if (port == id_CLKHF)
+            return TMG_GEN_CLOCK;
+        return TMG_IGNORE;
+    } else if (cell->type == id_SB_GB) {
+        if (port == id_GLOBAL_BUFFER_OUTPUT)
+            return TMG_COMB_OUTPUT;
+        return TMG_COMB_INPUT;
+    } else if (cell->type == id_SB_WARMBOOT) {
+        return TMG_ENDPOINT;
+    }
+    log_error("no timing info for port '%s' of cell type '%s'\n", port.c_str(this), cell->type.c_str(this));
 }
 
 bool Arch::isGlobalNet(const NetInfo *net) const
diff --git a/ice40/arch.h b/ice40/arch.h
index 62a637ae..561d75c3 100644
--- a/ice40/arch.h
+++ b/ice40/arch.h
@@ -400,10 +400,10 @@ struct Arch : BaseCtx
     mutable std::unordered_map<Loc, int> bel_by_loc;
 
     std::vector<bool> bel_carry;
-    std::vector<CellInfo*> bel_to_cell;
-    std::vector<NetInfo*> wire_to_net;
-    std::vector<NetInfo*> pip_to_net;
-    std::vector<NetInfo*> switches_locked;
+    std::vector<CellInfo *> bel_to_cell;
+    std::vector<NetInfo *> wire_to_net;
+    std::vector<NetInfo *> pip_to_net;
+    std::vector<NetInfo *> switches_locked;
 
     ArchArgs args;
     Arch(ArchArgs args);
@@ -411,6 +411,7 @@ struct Arch : BaseCtx
     std::string getChipName() const;
 
     IdString archId() const { return id("ice40"); }
+    ArchArgs archArgs() const { return args; }
     IdString archArgsToId(ArchArgs args) const;
 
     // -------------------------------------------------
@@ -782,16 +783,15 @@ struct Arch : BaseCtx
     // Get the delay through a cell from one port to another, returning false
     // if no path exists
     bool getCellDelay(const CellInfo *cell, IdString fromPort, IdString toPort, DelayInfo &delay) const;
-    // Get the associated clock to a port, or empty if the port is combinational
-    IdString getPortClock(const CellInfo *cell, IdString port) const;
-    // Return true if a port is a clock
-    bool isClockPort(const CellInfo *cell, IdString port) const;
+    // Get the port class, also setting clockDomain if applicable
+    TimingPortClass getPortTimingClass(const CellInfo *cell, IdString port, IdString &clockDomain) const;
     // Return true if a port is a net
     bool isGlobalNet(const NetInfo *net) const;
 
     // -------------------------------------------------
 
-    // Perform placement validity checks, returning false on failure (all implemented in arch_place.cc)
+    // Perform placement validity checks, returning false on failure (all
+    // implemented in arch_place.cc)
 
     // Whether or not a given cell can be placed at a given Bel
     // This is not intended for Bel type checks, but finer-grained constraints
@@ -805,7 +805,8 @@ struct Arch : BaseCtx
     bool logicCellsCompatible(const std::vector<const CellInfo *> &cells) const;
 
     // -------------------------------------------------
-    // Assign architecure-specific arguments to nets and cells, which must be called between packing or further
+    // Assign architecure-specific arguments to nets and cells, which must be
+    // called between packing or further
     // netlist modifications, and validity checks
     void assignArchInfo();
     void assignCellInfo(CellInfo *cell);
diff --git a/ice40/main.cc b/ice40/main.cc
index 78236af1..2818a3ad 100644
--- a/ice40/main.cc
+++ b/ice40/main.cc
@@ -2,6 +2,7 @@
  *  nextpnr -- Next Generation Place and Route
  *
  *  Copyright (C) 2018  Clifford Wolf <clifford@symbioticeda.com>
+ *  Copyright (C) 2018  Miodrag Milanovic <miodrag@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
@@ -19,391 +20,144 @@
 
 #ifdef MAIN_EXECUTABLE
 
-#ifndef NO_GUI
-#include <QApplication>
-#include "application.h"
-#include "mainwindow.h"
-#endif
-#ifndef NO_PYTHON
-#include "pybindings.h"
-#endif
-
-#include <boost/filesystem/convenience.hpp>
-#include <boost/program_options.hpp>
-#include <boost/property_tree/json_parser.hpp>
-#include <boost/property_tree/ptree.hpp>
 #include <fstream>
-#include <iostream>
 #include "bitstream.h"
+#include "command.h"
 #include "design_utils.h"
 #include "jsonparse.h"
 #include "log.h"
-#include "nextpnr.h"
 #include "pcf.h"
 #include "timing.h"
-#include "version.h"
 
 USING_NEXTPNR_NAMESPACE
 
-void conflicting_options(const boost::program_options::variables_map &vm, const char *opt1, const char *opt2)
+class Ice40CommandHandler : public CommandHandler
 {
-    if (vm.count(opt1) && !vm[opt1].defaulted() && vm.count(opt2) && !vm[opt2].defaulted()) {
-        std::string msg = "Conflicting options '" + std::string(opt1) + "' and '" + std::string(opt1) + "'.";
-        log_error("%s\n", msg.c_str());
-    }
-}
-
-int main(int argc, char *argv[])
+  public:
+    Ice40CommandHandler(int argc, char **argv);
+    virtual ~Ice40CommandHandler(){};
+    std::unique_ptr<Context> createContext() override;
+    void setupArchContext(Context *ctx) override;
+    void validate() override;
+    void customAfterLoad(Context *ctx) override;
+    void customBitstream(Context *ctx) override;
+
+  protected:
+    po::options_description getArchOptions();
+};
+
+Ice40CommandHandler::Ice40CommandHandler(int argc, char **argv) : CommandHandler(argc, argv) {}
+
+po::options_description Ice40CommandHandler::getArchOptions()
 {
-    try {
-        namespace po = boost::program_options;
-        namespace pt = boost::property_tree;
-        int rc = 0;
-        std::string str;
-
-        log_files.push_back(stdout);
-
-        po::options_description options("Allowed options");
-        options.add_options()("help,h", "show help");
-        options.add_options()("verbose,v", "verbose output");
-        options.add_options()("debug", "debug output");
-        options.add_options()("force,f", "keep running after errors");
-#ifndef NO_GUI
-        options.add_options()("gui", "start gui");
-#endif
-        options.add_options()("pack-only", "pack design only without placement or routing");
-
-        po::positional_options_description pos;
-#ifndef NO_PYTHON
-        options.add_options()("run", po::value<std::vector<std::string>>(), "python file to execute");
-        pos.add("run", -1);
-#endif
-        options.add_options()("json", po::value<std::string>(), "JSON design file to ingest");
-        options.add_options()("pcf", po::value<std::string>(), "PCF constraints file to ingest");
-        options.add_options()("asc", po::value<std::string>(), "asc bitstream file to write");
-        options.add_options()("read", po::value<std::string>(), "asc bitstream file to read");
-        options.add_options()("seed", po::value<int>(), "seed value for random number generator");
-        options.add_options()("slack_redist_iter", po::value<int>(),
-                              "number of iterations between slack redistribution");
-        options.add_options()("cstrweight", po::value<float>(),
-                              "placer weighting for relative constraint satisfaction");
-
-        options.add_options()("version,V", "show version");
-        options.add_options()("tmfuzz", "run path delay estimate fuzzer");
-        options.add_options()("test", "check architecture database integrity");
+    po::options_description specific("Architecture specific options");
 #ifdef ICE40_HX1K_ONLY
-        options.add_options()("hx1k", "set device type to iCE40HX1K");
+    specific.add_options()("hx1k", "set device type to iCE40HX1K");
 #else
-        options.add_options()("lp384", "set device type to iCE40LP384");
-        options.add_options()("lp1k", "set device type to iCE40LP1K");
-        options.add_options()("lp8k", "set device type to iCE40LP8K");
-        options.add_options()("hx1k", "set device type to iCE40HX1K");
-        options.add_options()("hx8k", "set device type to iCE40HX8K");
-        options.add_options()("up5k", "set device type to iCE40UP5K");
+    specific.add_options()("lp384", "set device type to iCE40LP384");
+    specific.add_options()("lp1k", "set device type to iCE40LP1K");
+    specific.add_options()("lp8k", "set device type to iCE40LP8K");
+    specific.add_options()("hx1k", "set device type to iCE40HX1K");
+    specific.add_options()("hx8k", "set device type to iCE40HX8K");
+    specific.add_options()("up5k", "set device type to iCE40UP5K");
 #endif
-        options.add_options()("freq", po::value<double>(), "set target frequency for design in MHz");
-        options.add_options()("no-tmdriv", "disable timing-driven placement");
-        options.add_options()("package", po::value<std::string>(), "set device package");
-        options.add_options()("save", po::value<std::string>(), "project file to write");
-        options.add_options()("load", po::value<std::string>(), "project file to read");
-
-        po::variables_map vm;
-        try {
-            po::parsed_options parsed = po::command_line_parser(argc, argv).options(options).positional(pos).run();
-
-            po::store(parsed, vm);
-
-            po::notify(vm);
-        } catch (std::exception &e) {
-            std::cout << e.what() << "\n";
-            return 1;
-        }
-
-        conflicting_options(vm, "read", "json");
-#ifndef ICE40_HX1K_ONLY
-        if ((vm.count("lp384") + vm.count("lp1k") + vm.count("lp8k") + vm.count("hx1k") + vm.count("hx8k") +
-             vm.count("up5k")) > 1)
-            log_error("Only one device type can be set\n");
-#endif
-        if (vm.count("help") || argc == 1) {
-        help:
-            std::cout << boost::filesystem::basename(argv[0])
-                      << " -- Next Generation Place and Route (git "
-                         "sha1 " GIT_COMMIT_HASH_STR ")\n";
-            std::cout << "\n";
-            std::cout << options << "\n";
-            return argc != 1;
-        }
-
-        if (vm.count("version")) {
-            std::cout << boost::filesystem::basename(argv[0])
-                      << " -- Next Generation Place and Route (git "
-                         "sha1 " GIT_COMMIT_HASH_STR ")\n";
-            return 1;
-        }
-
-        if (vm.count("load")) {
-            try {
-                pt::ptree root;
-                std::string filename = vm["load"].as<std::string>();
-                pt::read_json(filename, root);
-                log_info("Loading project %s...\n", filename.c_str());
-                log_break();
-
-                bool isLoadingGui = vm.count("gui") > 0;
-                std::string ascOutput;
-                if (vm.count("asc"))
-                    ascOutput = vm["asc"].as<std::string>();
-                vm.clear();
-
-                int version = root.get<int>("project.version");
-                if (version != 1)
-                    log_error("Wrong project format version.\n");
-
-                std::string arch_name = root.get<std::string>("project.arch.name");
-                if (arch_name != "ice40")
-                    log_error("Unsuported project architecture.\n");
-
-                std::string arch_type = root.get<std::string>("project.arch.type");
-                vm.insert(std::make_pair(arch_type, po::variable_value()));
-
-                std::string arch_package = root.get<std::string>("project.arch.package");
-                vm.insert(std::make_pair("package", po::variable_value(arch_package, false)));
+    specific.add_options()("package", po::value<std::string>(), "set device package");
+    specific.add_options()("pcf", po::value<std::string>(), "PCF constraints file to ingest");
+    specific.add_options()("asc", po::value<std::string>(), "asc bitstream file to write");
+    specific.add_options()("read", po::value<std::string>(), "asc bitstream file to read");
+    specific.add_options()("tmfuzz", "run path delay estimate fuzzer");
+    return specific;
+}
+void Ice40CommandHandler::validate()
+{
+    conflicting_options(vm, "read", "json");
+    if ((vm.count("lp384") + vm.count("lp1k") + vm.count("lp8k") + vm.count("hx1k") + vm.count("hx8k") +
+         vm.count("up5k")) > 1)
+        log_error("Only one device type can be set\n");
+}
 
-                auto project = root.get_child("project");
-                if (project.count("input")) {
-                    auto input = project.get_child("input");
-                    if (input.count("json"))
-                        vm.insert(std::make_pair("json", po::variable_value(input.get<std::string>("json"), false)));
-                    if (input.count("pcf"))
-                        vm.insert(std::make_pair("pcf", po::variable_value(input.get<std::string>("pcf"), false)));
-                }
-                if (project.count("params")) {
-                    auto params = project.get_child("params");
-                    if (params.count("freq"))
-                        vm.insert(std::make_pair("freq", po::variable_value(params.get<double>("freq"), false)));
-                    if (params.count("seed"))
-                        vm.insert(std::make_pair("seed", po::variable_value(params.get<int>("seed"), false)));
-                }
-                if (!ascOutput.empty())
-                    vm.insert(std::make_pair("asc", po::variable_value(ascOutput, false)));
-                if (isLoadingGui)
-                    vm.insert(std::make_pair("gui", po::variable_value()));
-                po::notify(vm);
-            } catch (...) {
-                log_error("Error loading project file.\n");
-            }
-        }
+void Ice40CommandHandler::customAfterLoad(Context *ctx)
+{
+    if (vm.count("pcf")) {
+        std::ifstream pcf(vm["pcf"].as<std::string>());
+        if (!apply_pcf(ctx, pcf))
+            log_error("Loading PCF failed.\n");
+    }
+}
+void Ice40CommandHandler::customBitstream(Context *ctx)
+{
+    if (vm.count("asc")) {
+        std::string filename = vm["asc"].as<std::string>();
+        std::ofstream f(filename);
+        write_asc(ctx, f);
+    }
+}
 
-        ArchArgs chipArgs;
+void Ice40CommandHandler::setupArchContext(Context *ctx)
+{
+    if (vm.count("tmfuzz"))
+        ice40DelayFuzzerMain(ctx);
+
+    if (vm.count("read")) {
+        std::string filename = vm["read"].as<std::string>();
+        std::ifstream f(filename);
+        if (!read_asc(ctx, f))
+            log_error("Loading ASC failed.\n");
+    }
+}
 
-        if (vm.count("lp384")) {
-            if (chipArgs.type != ArchArgs::NONE)
-                goto help;
-            chipArgs.type = ArchArgs::LP384;
-            chipArgs.package = "qn32";
-        }
+std::unique_ptr<Context> Ice40CommandHandler::createContext()
+{
+    if (vm.count("lp384")) {
+        chipArgs.type = ArchArgs::LP384;
+        chipArgs.package = "qn32";
+    }
 
-        if (vm.count("lp1k")) {
-            if (chipArgs.type != ArchArgs::NONE)
-                goto help;
-            chipArgs.type = ArchArgs::LP1K;
-            chipArgs.package = "tq144";
-        }
+    if (vm.count("lp1k")) {
+        chipArgs.type = ArchArgs::LP1K;
+        chipArgs.package = "tq144";
+    }
 
-        if (vm.count("lp8k")) {
-            if (chipArgs.type != ArchArgs::NONE)
-                goto help;
-            chipArgs.type = ArchArgs::LP8K;
-            chipArgs.package = "ct256";
-        }
+    if (vm.count("lp8k")) {
+        chipArgs.type = ArchArgs::LP8K;
+        chipArgs.package = "ct256";
+    }
 
-        if (vm.count("hx1k")) {
-            if (chipArgs.type != ArchArgs::NONE)
-                goto help;
-            chipArgs.type = ArchArgs::HX1K;
-            chipArgs.package = "tq144";
-        }
+    if (vm.count("hx1k")) {
+        chipArgs.type = ArchArgs::HX1K;
+        chipArgs.package = "tq144";
+    }
 
-        if (vm.count("hx8k")) {
-            if (chipArgs.type != ArchArgs::NONE)
-                goto help;
-            chipArgs.type = ArchArgs::HX8K;
-            chipArgs.package = "ct256";
-        }
+    if (vm.count("hx8k")) {
+        chipArgs.type = ArchArgs::HX8K;
+        chipArgs.package = "ct256";
+    }
 
-        if (vm.count("up5k")) {
-            if (chipArgs.type != ArchArgs::NONE)
-                goto help;
-            chipArgs.type = ArchArgs::UP5K;
-            chipArgs.package = "sg48";
-        }
+    if (vm.count("up5k")) {
+        chipArgs.type = ArchArgs::UP5K;
+        chipArgs.package = "sg48";
+    }
 
-        if (chipArgs.type == ArchArgs::NONE) {
-            chipArgs.type = ArchArgs::HX1K;
-            chipArgs.package = "tq144";
-        }
+    if (chipArgs.type == ArchArgs::NONE) {
+        chipArgs.type = ArchArgs::HX1K;
+        chipArgs.package = "tq144";
+    }
 #ifdef ICE40_HX1K_ONLY
-        if (chipArgs.type != ArchArgs::HX1K) {
-            std::cout << "This version of nextpnr-ice40 is built with "
-                         "HX1K-support "
-                         "only.\n";
-            return 1;
-        }
-#endif
-
-        if (vm.count("package"))
-            chipArgs.package = vm["package"].as<std::string>();
-
-        if (vm.count("save")) {
-            Context ctx(chipArgs);
-            std::string filename = vm["save"].as<std::string>();
-            std::ofstream f(filename);
-            pt::ptree root;
-            root.put("project.version", 1);
-            root.put("project.name", boost::filesystem::basename(filename));
-            root.put("project.arch.name", ctx.archId().c_str(&ctx));
-            root.put("project.arch.type", ctx.archArgsToId(chipArgs).c_str(&ctx));
-            root.put("project.arch.package", chipArgs.package);
-            if (vm.count("json"))
-                root.put("project.input.json", vm["json"].as<std::string>());
-            if (vm.count("pcf"))
-                root.put("project.input.pcf", vm["pcf"].as<std::string>());
-            if (vm.count("freq"))
-                root.put("project.params.freq", vm["freq"].as<double>());
-            if (vm.count("seed"))
-                root.put("project.params.seed", vm["seed"].as<int>());
-            pt::write_json(f, root);
-            return 1;
-        }
-
-        std::unique_ptr<Context> ctx = std::unique_ptr<Context>(new Context(chipArgs));
-
-        if (vm.count("verbose")) {
-            ctx->verbose = true;
-        }
-
-        if (vm.count("debug")) {
-            ctx->verbose = true;
-            ctx->debug = true;
-        }
-
-        if (vm.count("force")) {
-            ctx->force = true;
-        }
-
-        if (vm.count("seed")) {
-            ctx->rngseed(vm["seed"].as<int>());
-        }
-
-        if (vm.count("slack_redist_iter")) {
-            ctx->slack_redist_iter = vm["slack_redist_iter"].as<int>();
-            if (vm.count("freq") && vm["freq"].as<double>() == 0) {
-                ctx->auto_freq = true;
-#ifndef NO_GUI
-                if (!vm.count("gui"))
-#endif
-                    log_warning("Target frequency not specified. Will optimise for max frequency.\n");
-            }
-        }
-
-        if (vm.count("cstrweight")) {
-            ctx->placer_constraintWeight = vm["cstrweight"].as<float>();
-        }
-
-        if (vm.count("test"))
-            ctx->archcheck();
-
-        if (vm.count("tmfuzz"))
-            ice40DelayFuzzerMain(ctx.get());
-
-        if (vm.count("freq")) {
-            auto freq = vm["freq"].as<double>();
-            if (freq > 0)
-                ctx->target_freq = freq * 1e6;
-        }
-
-        ctx->timing_driven = true;
-        if (vm.count("no-tmdriv"))
-            ctx->timing_driven = false;
-
-        if (vm.count("read")) {
-            std::string filename = vm["read"].as<std::string>();
-            std::ifstream f(filename);
-            if (!read_asc(ctx.get(), f))
-                log_error("Loading ASC failed.\n");
-        }
-
-#ifndef NO_GUI
-        if (vm.count("gui")) {
-            Application a(argc, argv);
-            MainWindow w(std::move(ctx), chipArgs);
-            if (vm.count("json")) {
-                std::string filename = vm["json"].as<std::string>();
-                std::string pcf = "";
-                w.load_json(filename);
-                if (vm.count("pcf")) {
-                    pcf = vm["pcf"].as<std::string>();
-                    w.load_pcf(pcf);
-                }
-            }
-            w.show();
-
-            return a.exec();
-        }
+    if (chipArgs.type != ArchArgs::HX1K) {
+        log_error("This version of nextpnr-ice40 is built with HX1K-support only.\n");
+    }
 #endif
-        if (vm.count("json")) {
-            std::string filename = vm["json"].as<std::string>();
-            std::ifstream f(filename);
-            if (!parse_json_file(f, filename, ctx.get()))
-                log_error("Loading design failed.\n");
-
-            if (vm.count("pcf")) {
-                std::ifstream pcf(vm["pcf"].as<std::string>());
-                if (!apply_pcf(ctx.get(), pcf))
-                    log_error("Loading PCF failed.\n");
-            }
 
-            if (!ctx->pack() && !ctx->force)
-                log_error("Packing design failed.\n");
-            assign_budget(ctx.get());
-            ctx->check();
-            print_utilisation(ctx.get());
-            if (!vm.count("pack-only")) {
-                if (!ctx->place() && !ctx->force)
-                    log_error("Placing design failed.\n");
-                ctx->check();
-                if (!ctx->route() && !ctx->force)
-                    log_error("Routing design failed.\n");
-            }
-        }
+    if (vm.count("package"))
+        chipArgs.package = vm["package"].as<std::string>();
 
-        if (vm.count("asc")) {
-            std::string filename = vm["asc"].as<std::string>();
-            std::ofstream f(filename);
-            write_asc(ctx.get(), f);
-        }
-
-#ifndef NO_PYTHON
-        if (vm.count("run")) {
-            init_python(argv[0], true);
-            python_export_global("ctx", *ctx.get());
-
-            std::vector<std::string> files = vm["run"].as<std::vector<std::string>>();
-            for (auto filename : files)
-                execute_python_file(filename.c_str());
+    return std::unique_ptr<Context>(new Context(chipArgs));
+}
 
-            deinit_python();
-        }
-#endif
-        return rc;
-    } catch (log_execution_error_exception) {
-#if defined(_MSC_VER)
-        _exit(EXIT_FAILURE);
-#else
-        _Exit(EXIT_FAILURE);
-#endif
-    }
+int main(int argc, char *argv[])
+{
+    Ice40CommandHandler handler(argc, argv);
+    return handler.exec();
 }
 
 #endif
diff --git a/ice40/pcf.cc b/ice40/pcf.cc
index ac1c8598..410fa1c9 100644
--- a/ice40/pcf.cc
+++ b/ice40/pcf.cc
@@ -31,7 +31,7 @@ bool apply_pcf(Context *ctx, std::istream &in)
 {
     try {
         if (!in)
-            log_error("failed to open PCF file");
+            log_error("failed to open PCF file\n");
         std::string line;
         while (std::getline(in, line)) {
             size_t cstart = line.find("#");
diff --git a/ice40/project.cc b/ice40/project.cc
new file mode 100644
index 00000000..d1f1674a
--- /dev/null
+++ b/ice40/project.cc
@@ -0,0 +1,71 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Miodrag Milanovic <miodrag@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 "project.h"
+#include <boost/filesystem/convenience.hpp>
+#include <fstream>
+#include "log.h"
+#include "pcf.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+void ProjectHandler::saveArch(Context *ctx, pt::ptree &root)
+{
+    root.put("project.arch.package", ctx->archArgs().package);
+    // if(!pcfFilename.empty())
+    //      root.put("project.input.pcf", pcfFilename);
+}
+
+std::unique_ptr<Context> ProjectHandler::createContext(pt::ptree &root)
+{
+    ArchArgs chipArgs;
+    std::string arch_type = root.get<std::string>("project.arch.type");
+    if (arch_type == "lp384") {
+        chipArgs.type = ArchArgs::LP384;
+    }
+    if (arch_type == "lp1k") {
+        chipArgs.type = ArchArgs::LP1K;
+    }
+    if (arch_type == "lp8k") {
+        chipArgs.type = ArchArgs::LP8K;
+    }
+    if (arch_type == "hx1k") {
+        chipArgs.type = ArchArgs::HX1K;
+    }
+    if (arch_type == "hx8k") {
+        chipArgs.type = ArchArgs::HX8K;
+    }
+    if (arch_type == "up5k") {
+        chipArgs.type = ArchArgs::UP5K;
+    }
+    chipArgs.package = root.get<std::string>("project.arch.package");
+
+    return std::unique_ptr<Context>(new Context(chipArgs));
+}
+
+void ProjectHandler::loadArch(Context *ctx, pt::ptree &root, std::string path)
+{
+    auto input = root.get_child("project").get_child("input");
+    boost::filesystem::path pcf = boost::filesystem::path(path) / input.get<std::string>("pcf");
+    std::ifstream f(pcf.string());
+    if (!apply_pcf(ctx, f))
+        log_error("Loading PCF failed.\n");
+}
+
+NEXTPNR_NAMESPACE_END