nexus: Add routing FASM export

Signed-off-by: David Shah <dave@ds0.me>

4 files changed, 175 insertions, 4 deletions

diff --git a/nexus/arch.h b/nexus/arch.h
index 2f6c5f7e..f46f51c7 100644
--- a/nexus/arch.h
+++ b/nexus/arch.h
@@ -100,8 +100,15 @@ NPNR_PACKED_STRUCT(struct LocWireInfoPOD {
     RelPtr<BelPinPOD> bel_pins;
 });
 
+enum PipFlags
+{
+    PIP_FIXED_CONN = 0x8000,
+};
+
 NPNR_PACKED_STRUCT(struct PipInfoPOD {
     uint16_t from_wire, to_wire;
+    uint16_t flags;
+    uint16_t padding;
     int32_t tile_type;
 });
 
@@ -1115,7 +1122,16 @@ struct Arch : BaseCtx
     {
         return chip_canonical_wire(db, chip_info, tile, index);
     }
-
+    IdString pip_src_wire_name(PipId pip) const
+    {
+        int wire = pip_data(pip).from_wire;
+        return db->loctypes[chip_info->grid[pip.tile].loc_type].wires[wire].name;
+    }
+    IdString pip_dst_wire_name(PipId pip) const
+    {
+        int wire = pip_data(pip).to_wire;
+        return db->loctypes[chip_info->grid[pip.tile].loc_type].wires[wire].name;
+    }
     // -------------------------------------------------
 
     NeighWireRange neigh_wire_range(WireId wire) const
@@ -1136,6 +1152,9 @@ struct Arch : BaseCtx
     // -------------------------------------------------
 
     bool nexus_logic_tile_valid(LogicTileStatus &lts) const;
+
+    // -------------------------------------------------
+    void write_fasm(std::ostream &out) const;
 };
 
 NEXTPNR_NAMESPACE_END
diff --git a/nexus/bba_version.inc b/nexus/bba_version.inc
index 0cfbf088..00750edc 100644
--- a/nexus/bba_version.inc
+++ b/nexus/bba_version.inc
@@ -1 +1 @@
-2
+3
diff --git a/nexus/fasm.cc b/nexus/fasm.cc
new file mode 100644
index 00000000..36656ec4
--- /dev/null
+++ b/nexus/fasm.cc
@@ -0,0 +1,143 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2020  David Shah <dave@ds0.me>
+ *
+ *
+ *  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 "log.h"
+#include "nextpnr.h"
+#include "util.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+namespace {
+struct NexusFasmWriter
+{
+    const Context *ctx;
+    std::ostream &out;
+    std::vector<std::string> fasm_ctx;
+
+    void push(const std::string &x) { fasm_ctx.push_back(x); }
+
+    void pop() { fasm_ctx.pop_back(); }
+
+    void pop(int N)
+    {
+        for (int i = 0; i < N; i++)
+            fasm_ctx.pop_back();
+    }
+    bool last_was_blank = true;
+    void blank()
+    {
+        if (!last_was_blank)
+            out << std::endl;
+        last_was_blank = true;
+    }
+
+    void write_prefix()
+    {
+        for (auto &x : fasm_ctx)
+            out << x << ".";
+        last_was_blank = false;
+    }
+
+    void write_bit(const std::string &name, bool value = true)
+    {
+        if (value) {
+            write_prefix();
+            out << name << std::endl;
+        }
+    }
+    void write_comment(const std::string &cmt) { out << "# " << cmt << std::endl; }
+
+    void write_vector(const std::string &name, const std::vector<bool> &value, bool invert = false)
+    {
+        write_prefix();
+        out << name << " = " << int(value.size()) << "'b";
+        for (auto bit : boost::adaptors::reverse(value))
+            out << ((bit ^ invert) ? '1' : '0');
+        out << std::endl;
+    }
+
+    void write_int_vector(const std::string &name, uint64_t value, int width, bool invert = false)
+    {
+        std::vector<bool> bits(width, false);
+        for (int i = 0; i < width; i++)
+            bits[i] = (value & (1ULL << i)) != 0;
+        write_vector(name, bits, invert);
+    }
+
+    NexusFasmWriter(const Context *ctx, std::ostream &out) : ctx(ctx), out(out) {}
+    std::string tile_name(int loc, const PhysicalTileInfoPOD &tile)
+    {
+        int r = loc / ctx->chip_info->width;
+        int c = loc % ctx->chip_info->width;
+        return stringf("%sR%dC%d__%s", ctx->nameOf(tile.prefix), r, c, ctx->nameOf(tile.tiletype));
+    }
+    const PhysicalTileInfoPOD &tile_by_type_and_loc(int loc, IdString type)
+    {
+        auto &ploc = ctx->chip_info->grid[loc];
+        for (int i = 0; i < ploc.num_phys_tiles; i++) {
+            if (ploc.phys_tiles[i].tiletype == type.index)
+                return ploc.phys_tiles[i];
+        }
+        log_error("No tile of type %s found at location R%dC%d", ctx->nameOf(type), loc / ctx->chip_info->width,
+                  loc % ctx->chip_info->width);
+    }
+    std::string escape_name(const std::string &name)
+    {
+        std::string escaped;
+        for (char c : name) {
+            if (c == ':')
+                escaped += "__";
+            else
+                escaped += c;
+        }
+        return escaped;
+    }
+    void write_pip(PipId pip)
+    {
+        auto &pd = ctx->pip_data(pip);
+        if (pd.flags & PIP_FIXED_CONN)
+            return;
+        std::string tile = tile_name(pip.tile, tile_by_type_and_loc(pip.tile, pd.tile_type));
+        std::string source_wire = escape_name(ctx->pip_src_wire_name(pip).str(ctx));
+        std::string dest_wire = escape_name(ctx->pip_src_wire_name(pip).str(ctx));
+        write_bit(stringf("%s.PIP.%s.%s", tile.c_str(), dest_wire.c_str(), source_wire.c_str()));
+    }
+    void write_net(const NetInfo *net)
+    {
+        write_comment(stringf("Net %s", ctx->nameOf(net)));
+        std::set<PipId> sorted_pips;
+        for (auto &w : net->wires)
+            sorted_pips.insert(w.second.pip);
+        for (auto p : sorted_pips)
+            write_pip(p);
+        blank();
+    }
+    void operator()()
+    {
+        // Write routing
+        for (auto n : sorted(ctx->nets)) {
+            write_net(n.second);
+        }
+    }
+};
+} // namespace
+
+void Arch::write_fasm(std::ostream &out) const { NexusFasmWriter(getCtx(), out)(); }
+
+NEXTPNR_NAMESPACE_END
diff --git a/nexus/main.cc b/nexus/main.cc
index 77f739a8..9549a573 100644
--- a/nexus/main.cc
+++ b/nexus/main.cc
@@ -49,11 +49,20 @@ po::options_description NexusCommandHandler::getArchOptions()
     po::options_description specific("Architecture specific options");
     specific.add_options()("chipdb", po::value<std::string>(), "name of chip database binary");
     specific.add_options()("device", po::value<std::string>(), "device name");
-
+    specific.add_options()("fasm", po::value<std::string>(), "fasm file to write");
     return specific;
 }
 
-void NexusCommandHandler::customBitstream(Context *ctx) {}
+void NexusCommandHandler::customBitstream(Context *ctx)
+{
+    if (vm.count("fasm")) {
+        std::string filename = vm["fasm"].as<std::string>();
+        std::ofstream out(filename);
+        if (!out)
+            log_error("Failed to open output FASM file %s.\n", filename.c_str());
+        ctx->write_fasm(out);
+    }
+}
 
 std::unique_ptr<Context> NexusCommandHandler::createContext(std::unordered_map<std::string, Property> &values)
 {