diff --git a/common/command.cc b/common/command.cc
new file mode 100644
index 00000000..aae7ed36
--- /dev/null
+++ b/common/command.cc
@@ -0,0 +1,246 @@
+/*
+ *  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 "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()("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());
+            }
+        } 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 (!ctx->pack() && !ctx->force)
+            log_error("Packing design failed.\n");
+        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
+    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 = 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..e6595f6a
--- /dev/null
+++ b/common/command.h
@@ -0,0 +1,68 @@
+/*
+ *  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"
+
+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;
+};
+
+NEXTPNR_NAMESPACE_END
+
+#endif // COMMAND_H
diff --git a/ecp5/main.cc b/ecp5/main.cc
index dde3ffed..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
 
+class ECP5CommandHandler : public CommandHandler
+{
+  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;
+
+  protected:
+    po::options_description getArchOptions();
+};
+
+ECP5CommandHandler::ECP5CommandHandler(int argc, char **argv) : CommandHandler(argc, argv) {}
+
+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");
+}
+
+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, basecfg, textcfg);
+}
+
+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));
+}
+
 int main(int argc, char *argv[])
 {
-    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;
-        }
-
-        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;
-        }
-
-        ArchArgs args;
-        args.type = ArchArgs::LFE5U_45F;
-
-        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");
-
-            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);
-        }
-
-#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
-        return rc;
-    } catch (log_execution_error_exception) {
-#if defined(_MSC_VER)
-        _exit(EXIT_FAILURE);
-#else
-        _Exit(EXIT_FAILURE);
-#endif
-    }
+    ECP5CommandHandler handler(argc, argv);
+    return handler.exec();
 }
 
 #endif
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
 
+class GenericCommandHandler : public CommandHandler
+{
+  public:
+    GenericCommandHandler(int argc, char **argv);
+    virtual ~GenericCommandHandler(){};
+    std::unique_ptr<Context> createContext() override;
+    void setupArchContext(Context *ctx) override{};
+    void customBitstream(Context *ctx) override;
+
+  protected:
+    po::options_description getArchOptions();
+};
+
+GenericCommandHandler::GenericCommandHandler(int argc, char **argv) : CommandHandler(argc, argv) {}
+
+po::options_description GenericCommandHandler::getArchOptions()
+{
+    po::options_description specific("Architecture specific options");
+    specific.add_options()("generic", "set device type to generic");
+    return specific;
+}
+
+void GenericCommandHandler::customBitstream(Context *ctx) { log_error("Here is when bitstream gets created"); }
+
+std::unique_ptr<Context> GenericCommandHandler::createContext()
+{
+    return std::unique_ptr<Context>(new Context(chipArgs));
+}
+
 int main(int argc, char *argv[])
 {
-    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;
-        }
-
-        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;
-        }
-
-        ArchArgs chipArgs{};
-        std::unique_ptr<Context> ctx = std::unique_ptr<Context>(new Context(chipArgs));
-
-        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());
-
-            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
-
-        return rc;
-    } catch (log_execution_error_exception) {
-#if defined(_MSC_VER)
-        _exit(EXIT_FAILURE);
-#else
-        _Exit(EXIT_FAILURE);
-#endif
-    }
+    GenericCommandHandler handler(argc, argv);
+    return handler.exec();
 }
 
 #endif
diff --git a/ice40/main.cc b/ice40/main.cc
index 358bf3c5..a98ca07e 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
@@ -19,390 +20,145 @@
 
 #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());
+  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()
+{
+    po::options_description specific("Architecture specific options");
+#ifdef ICE40_HX1K_ONLY
+    specific.add_options()("hx1k", "set device type to iCE40HX1K");
+#else
+    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
+    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");
+    specific.add_options()("pack-only", "pack design only without placement or routing");
+    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");
+}
+
+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);
+    }
+}
+
+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");
+    }
+}
+
+std::unique_ptr<Context> Ice40CommandHandler::createContext()
+{
+    if (vm.count("lp384")) {
+        chipArgs.type = ArchArgs::LP384;
+        chipArgs.package = "qn32";
+    }
+
+    if (vm.count("lp1k")) {
+        chipArgs.type = ArchArgs::LP1K;
+        chipArgs.package = "tq144";
+    }
+
+    if (vm.count("lp8k")) {
+        chipArgs.type = ArchArgs::LP8K;
+        chipArgs.package = "ct256";
+    }
+
+    if (vm.count("hx1k")) {
+        chipArgs.type = ArchArgs::HX1K;
+        chipArgs.package = "tq144";
+    }
+
+    if (vm.count("hx8k")) {
+        chipArgs.type = ArchArgs::HX8K;
+        chipArgs.package = "ct256";
+    }
+
+    if (vm.count("up5k")) {
+        chipArgs.type = ArchArgs::UP5K;
+        chipArgs.package = "sg48";
+    }
+
+    if (chipArgs.type == ArchArgs::NONE) {
+        chipArgs.type = ArchArgs::HX1K;
+        chipArgs.package = "tq144";
+    }
+#ifdef ICE40_HX1K_ONLY
+    if (chipArgs.type != ArchArgs::HX1K) {
+        log_error("This version of nextpnr-ice40 is built with HX1K-support only.\n");
+    }
+#endif
+
+    if (vm.count("package"))
+        chipArgs.package = vm["package"].as<std::string>();
+
+    return std::unique_ptr<Context>(new Context(chipArgs));
+}
 
 int main(int argc, char *argv[])
 {
-    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");
-#ifdef ICE40_HX1K_ONLY
-        options.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");
-#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)));
-
-                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");
-            }
-        }
-
-        ArchArgs chipArgs;
-
-        if (vm.count("lp384")) {
-            if (chipArgs.type != ArchArgs::NONE)
-                goto help;
-            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("lp8k")) {
-            if (chipArgs.type != ArchArgs::NONE)
-                goto help;
-            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("hx8k")) {
-            if (chipArgs.type != ArchArgs::NONE)
-                goto help;
-            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 (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();
-        }
-#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");
-            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("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());
-
-            deinit_python();
-        }
-#endif
-        return rc;
-    } catch (log_execution_error_exception) {
-#if defined(_MSC_VER)
-        _exit(EXIT_FAILURE);
-#else
-        _Exit(EXIT_FAILURE);
-#endif
-    }
+    Ice40CommandHandler handler(argc, argv);
+    return handler.exec();
 }
 
 #endif