added mpardemo
[slipway.git] / src / edu / berkeley / slipway / MPARDemo.java
diff --git a/src/edu/berkeley/slipway/MPARDemo.java b/src/edu/berkeley/slipway/MPARDemo.java
new file mode 100644 (file)
index 0000000..2a2ca00
--- /dev/null
@@ -0,0 +1,798 @@
+import com.atmel.fpslic.*;
+import byucc.edif.tools.merge.*;
+import byucc.edif.*;
+import java.io.*;
+import java.util.*;
+import edu.berkeley.slipway.*;
+import com.atmel.fpslic.*;
+import static com.atmel.fpslic.FpslicConstants.*;
+
+public class MPARDemo {
+
+    public static final double alphaParameter = 00.9;
+    public static final double betaParameter  = 20.0;
+    public static final double gammaParameter =  1.0;
+
+    public static class FlatNetlist {
+
+        private HashMap<String,Integer> ids = new HashMap<String,Integer>();
+
+        public HashSet<Node> nodes = new HashSet<Node>();
+        public HashSet<Net>  nets  = new HashSet<Net>();
+
+        /** a node is some primitive element; a potential configuration of a CLB */
+        public class Node {
+            public PhysicalDevice.PhysicalCell physicalCell = null;
+            private final String type;
+            private final int    id;
+
+            public int x = -1;
+            public int y = -1;
+
+            private HashMap<String,Port> ports = new HashMap<String,Port>();
+
+            public Node(String type) {
+                nodes.add(this);
+                this.type = type.toLowerCase();
+                Integer num = ids.get(type);
+                this.id = num == null ? 0 : num.intValue();
+                ids.put(type, this.id+1);
+            }
+            public String getType() { return type; }
+            public String toString() {
+                if (x==-1 || y==-1)
+                    return type + "["+id+"]";
+                return type + "@("+x+","+y+")";
+            }
+            public Port getPort(String name, boolean driver) {
+                Port p = ports.get(name);
+                if (p==null) ports.put(name, p = new Port(name, driver));
+                return p;
+            }
+
+            public Fpslic.Cell getPlacement(Fpslic fpslic) { return fpslic.cell(x, y); }
+            public void place(Fpslic fpslic) {
+                Fpslic.Cell cell = fpslic.cell(x,y);
+                cell.c(XLUT);
+                cell.b(false);
+                cell.f(false);
+                cell.xi(NW);
+                cell.yi(EAST);
+                if      (type.equals("and2"))    cell.xlut(LUT_SELF & LUT_OTHER);
+                else if (type.equals("or2"))     cell.xlut(LUT_SELF | LUT_OTHER);
+                else if (type.equals("xor2"))    cell.xlut(LUT_SELF ^ LUT_OTHER);
+                else if (type.equals("buf"))     cell.xlut(LUT_SELF);
+                else if (type.equals("inv"))     cell.xlut(~LUT_SELF);
+                else if (type.equals("cell0"))   return;
+            }
+
+            private int portIndex = 0;
+
+            /** a port is an input or output to a Node */
+            public class Port {
+                private final String name;
+                private final boolean driver;
+                Net    net;
+                public final int index;
+                public Port(String name, boolean driver) {
+                    this.name = name;
+                    this.driver = driver;
+                    this.index = driver ? 0 : portIndex++;
+                }
+                public String toString() { return Node.this + "." + name; }
+                public Node getNode() { return Node.this; }
+                public void connect(Port p) {
+                    if (net != null)          { net.add(p);
+                    } else if (p.net != null) { p.net.add(this);
+                    } else {
+                        new Net().add(this);
+                        this.net.add(p);
+                    }
+                }
+                public void route(Fpslic fpslic, Port[] dests, PhysicalDevice pd) {
+                    PhysicalDevice.PhysicalNet[] destsp = new PhysicalDevice.PhysicalNet[dests.length];
+                    for(int i=0; i<dests.length; i++) {
+                        Port dest = dests[i];
+                        switch(dest.index) {
+                            case 0: destsp[i] = dest.getNode().physicalCell.getNet("xi"); break;
+                            case 1: destsp[i] = dest.getNode().physicalCell.getNet("yi"); break;
+                            default: throw new Error();
+                        }
+                    }
+                    //System.out.println(physicalCell.getNet("out"));
+                    //System.out.println(destsp[0]);
+                    pd.route(physicalCell.getNet("out"), destsp);
+
+                    /*
+                    Fpslic.Cell driverCell = fpslic.cell(getNode().x,getNode().y);
+                    Fpslic.Cell destCell   = fpslic.cell(dest.getNode().x,dest.getNode().y);
+                    boolean[] hblocked = new boolean[5];
+                    boolean[] vblocked = new boolean[5];
+                    hblocked[3] = true;
+                    vblocked[3] = true;
+                    int minx = Math.min(getNode().x, dest.getNode().x);
+                    int miny = Math.min(getNode().y, dest.getNode().y);
+                    int maxx = Math.max(getNode().x, dest.getNode().x);
+                    int maxy = Math.max(getNode().y, dest.getNode().y);
+                    for(int cx = 0; cx <= 3; cx++) {
+                        Fpslic.Cell c = fpslic.cell(cx, getNode().y);
+                        for(int i=0; i<5; i++)
+                            hblocked[i] |= (c.hx(i) && !c.equals(driverCell));
+                    }
+                    for(int cy = 0; cy <= 3; cy++) {
+                        Fpslic.Cell c = fpslic.cell(dest.getNode().x, cy);
+                        for(int i=0; i<5; i++)
+                            vblocked[i] |= (c.vx(i) && !c.equals(driverCell));
+                    }
+                    int free = 0;
+                    for(; free < 5; free++) if (!hblocked[free]) break;
+                    for(; free < 5; free++) if (!vblocked[free]) break;
+                    if (free >= 5) throw new RuntimeException("unroutable!");
+                    Fpslic.Cell turnCell = fpslic.cell(dest.getNode().x, getNode().y);
+                    driverCell.out(free, true);
+                    driverCell.h(free, true);
+                    turnCell.h(free, true);
+                    turnCell.v(free, true);
+                    switch(dest.index) {
+                        case 0: destCell.xi(L0 + free); break;
+                        case 1: destCell.yi(L0 + free); break;
+                        case 2: destCell.wi(L0 + free); break;
+                        case 3: destCell.zi(L0 + free); break;
+                        default: throw new RuntimeException("error");
+                    }
+                    destCell.v(free, true);
+                    System.out.println("route " + this + " -> " + dest + " on planes " + free);
+                    */
+                }
+            }
+        }
+
+        /** a Net is a collection of ports which are wired together */
+        public class Net implements Iterable<Node.Port> {
+            private Node.Port driver = null;
+            private HashSet<Node.Port> ports = new HashSet<Node.Port>();
+            public Net() { nets.add(this); }
+            public Iterator<Node.Port> iterator() { return ports.iterator(); }
+            public int getSize() { return ports.size(); }
+            public void route(Fpslic fpslic, PhysicalDevice pd) {
+                if (driver == null) return;
+                //System.out.println();
+                //System.out.println("routing " + this);
+                Node.Port[] dests = new Node.Port[ports.size() - (ports.contains(driver) ? 1 : 0)];
+                int i = 0;
+                for(Node.Port p : ports)
+                    if (p != driver)
+                        dests[i++] = p;
+                driver.route(fpslic, dests, pd);
+            }
+            public void add(Node.Port p) {
+                if (p.driver) {
+                    if (driver != null && driver != p)
+                        throw new RuntimeException("two drivers on a port!\n  "+driver+"\n  "+p);
+                    driver = p;
+                }
+                if (p.net==this || ports.contains(p)) return;
+                ports.add(p);
+                add(p.net);
+                p.net = this;
+            }
+            public void add(Net n) {
+                if (n==this || n==null) return;
+                for(Node.Port p : n) add(p);
+                nets.remove(n);
+            }
+            public String toString() {
+                StringBuffer ret = new StringBuffer();
+                ret.append(driver==null ? "()" : driver.toString());
+                ret.append(" -> ");
+                for(Node.Port p : this)
+                    if (p!=driver)
+                        ret.append(p+" ");
+                return ret.toString();
+            }
+        }
+
+
+        public HashMap<EdifCellInstance,FlatNetlist.Node> cache =
+            new HashMap<EdifCellInstance,FlatNetlist.Node>();
+        public HashMap<String,FlatNetlist.Node> top =
+            new HashMap<String,FlatNetlist.Node>();
+       
+        public FlatNetlist.Node createNode(EdifCellInstance eci, String portName) {
+            FlatNetlist.Node n = eci==null ? top.get(portName) : cache.get(eci);
+            if (n != null) return n;
+            if (eci==null) {
+                n = new FlatNetlist.Node("top_"+portName);
+                top.put(portName, n);
+                return n;
+            } else {
+                n = new FlatNetlist.Node(eci.getType());
+                cache.put(eci,n);
+            }
+            for(EdifPortRef epr : eci.getAllEPRs()) {
+                EdifPort ep = epr.getPort();
+                EdifNet  en = epr.getNet();
+                String name = ep.getOldName();
+                boolean driver = ep.getDirection()==ep.OUT;
+                if (eci==null) driver = !driver;
+                if (eci==null) name = driver ? "out" : "xi";
+                FlatNetlist.Node.Port p = n.getPort(name, driver);
+                for(EdifPortRef epr2 : en.getConnectedPortRefs()) {
+                    EdifCellInstance eci2 = epr2.getCellInstance();
+                    EdifPort ep2 = epr2.getPort();
+                    Node n2 = createNode(eci2, ep2.getOldName());
+                    driver = ep2.getDirection()==ep.OUT;
+                    name = ep2.getOldName();
+                    if (eci2==null) driver = !driver;
+                    if (eci2==null) name = driver ? "out" : "xi";
+                    FlatNetlist.Node.Port p2 = n2.getPort(name, driver);
+                    p.connect(p2);
+                }
+            }
+            return n;
+        }
+    }
+
+    /*
+      test code for inter-sector switchboxes
+    public static void main2() throws Exception {
+        Fpslic fpslic = new FtdiBoard();
+        // set up scan cell
+        fpslic.cell(23,15).h(3, true);
+        fpslic.cell(23,15).yi(L3);
+        fpslic.cell(23,15).ylut(0xAA);
+        fpslic.iob_right(15, true).enableOutput(WEST);
+        fpslic.cell(23,0).ylut(0x00);
+        fpslic.iob_right(0, true).enableOutput(WEST);
+        fpslic.flush();
+        for(int x=0; x<20; x++) {
+            for(int y=0; y<20; y++) {
+                for(int l=0; l<5; l++) {
+                    for(int v = 0; v <= 1; v++) {
+                        boolean vert = v==1;
+                        int newx = vert ? x   : x-1;
+                        int newy = vert ? y-1 : y;
+                        if (newx<0 || newy<0) continue;
+                        if (vert  && (y%4) != 0) continue;
+                        if (!vert && (x%4) != 0) continue;
+
+                        int layer = l;
+                        if (layer==3) continue;
+                        Fpslic.Cell c  = fpslic.cell(x, y);
+                        Fpslic.Cell c2 = fpslic.cell(newx, newy);
+                        Fpslic.SectorWire sw1 = vert ? c.vwire(layer)  : c.hwire(layer);
+                        Fpslic.SectorWire sw2 = vert ? c2.vwire(layer) : c2.hwire(layer);
+                        sw1.drives(sw2, true);
+
+                        c.c(YLUT);
+                        if (vert) c.v(L0 + layer, true);
+                        else      c.h(L0 + layer, true);
+                        c.out(L0 + layer, true);
+                        c.b(false);
+                        
+                        c2.yi(L0 + layer);
+                        if (vert) c2.v(L0 + layer, true);
+                        else      c2.h(L0 + layer, true);
+                        c2.ylut(LUT_SELF);
+                        c2.c(YLUT);
+                        c2.b(false);
+                        
+                        System.out.print(x+","+y+","+l+","+(vert?"v":"h")+": ");
+                        c.ylut(0x00);
+                        fpslic.flush();
+                        boolean good = scan(fpslic, c2)==0;
+                        if (!good) fails++;
+                        System.out.print(good ? "ok " : "bad ");
+                        c.ylut(0xff);
+                        fpslic.flush();
+                        good = scan(fpslic, c2)!=0;
+                        if (!good) fails++;
+                        System.out.print(good ? "ok " : "bad ");
+                        System.out.println();
+                        sw1.drives(sw2, false);
+                        if (vert) c.v(layer, false);
+                        else      c.h(layer, false);
+                        c.out(layer, false);
+                    }
+                }
+            }
+        }
+        System.out.println("fails = " + fails);
+        
+    }
+    public static int fails = 0;
+    */
+
+    public static void main(String[] s) throws Exception {
+        EdifEnvironment topEnv = new EdifEnvironment("top");
+        EdifLibraryManager elm = new EdifLibraryManager(topEnv);
+        EdifLibrary initLib = new EdifLibrary(elm, "initLib");
+        EdifEnvironment env = EdifMergeParser.parseAndMerge(s, initLib);
+        System.out.println("top is " + env.getTopCell());
+        FlatNetlist fnl = new FlatNetlist();
+
+        for(Iterator<EdifCellInstance> it = (Iterator<EdifCellInstance>)env.getTopCell().cellInstanceIterator();
+            it.hasNext();
+            ) {
+            FlatNetlist.Node n = fnl.createNode(it.next(), null);
+        }
+
+        Fpslic fpslic = new FtdiBoard();
+        PhysicalDevice pd = new PhysicalDevice(fpslic, 20, 20);
+
+        int px = 0;
+        int py = 0;
+
+        // crude map
+        Random rand = new Random();
+        boolean[][] used = new boolean[pd.width][pd.height];
+        for(FlatNetlist.Node n : fnl.nodes) {
+            while(true) {
+                px = Math.abs(rand.nextInt()) % pd.width;
+                py = Math.abs(rand.nextInt()) % pd.height;
+                if (!used[px][py]) {
+                    used[px][py] = true;
+                    n.x = px;
+                    n.y = py;
+                    n.physicalCell = pd.getCell(px, py);
+                    System.out.println("placed " + n + " at ("+px+","+py+")");
+                    n.place(fpslic);
+                    break;
+                }
+            }
+        }
+
+        int trial = 0;
+        while(true) {
+            System.out.println();
+            System.out.println("routing trial " + (++trial));
+            for(FlatNetlist.Net net : fnl.nets) {
+                if (net.getSize() <= 1) continue;
+                net.route(fpslic, pd);
+            }
+            double congestion = 0;
+            int overrouted = 0;
+            for(PhysicalDevice.PhysicalNet pn : pd.allPhysicalNets) {
+                if (pn.load > 1) {
+                    //System.out.println("overrouted: " + pn + ", congestion="+pn.congestion);
+                    overrouted++;
+                    congestion += pn.congestion;
+                }
+                pn.congestion = pn.congestion * alphaParameter;
+                if (pn.load > 1) {
+                    pn.congestion += betaParameter;
+                }
+                pn.load = 0;
+            }
+            System.out.println("  overrouted="+overrouted+", congestion="+congestion);
+            if (overrouted <= 0) break;
+            for(PhysicalDevice.PhysicalNet pn : pd.allPhysicalNets)
+                for(PhysicalDevice.PhysicalPip pip : pn) {
+                    pip.set(false);
+                }
+        }
+
+        // set up scan cell
+        fpslic.cell(23,15).h(3, true);
+        fpslic.cell(23,15).yi(L3);
+        fpslic.cell(23,15).ylut(0xAA);
+        fpslic.iob_right(15, true).enableOutput(WEST);
+        fpslic.cell(23,0).ylut(0x00);
+        fpslic.iob_right(0, true).enableOutput(WEST);
+        fpslic.flush();
+
+        int width = 8;
+        while(true) {
+            int a = Math.abs(rand.nextInt()) % (1 << width);
+            int b = Math.abs(rand.nextInt()) % (1 << width);
+            setInput(fnl, fpslic, "a",  a);
+            setInput(fnl, fpslic, "b",  b);
+            setInput(fnl, fpslic, "ci", 0);
+            int result = getOutput(fnl, fpslic, "out");
+            System.out.println(Integer.toString(a,16) + " + " +
+                               Integer.toString(b,16) + " = " +
+                               Integer.toString(result,16) +
+                               " [ " + (a+b==result ? "ok" : "bad" ) + " ] ");
+        }
+    }
+
+    public static class PhysicalDevice {
+        private final Fpslic fpslic;
+        
+        public final int width;
+        public final int height;
+        private final PhysicalNet[][][][] sectorWires;
+        private final PhysicalCell[][] cells;
+
+        public PhysicalCell getCell(int col, int row) {
+            if (col<0) return null;
+            if (row<0) return null;
+            if (col>=width) return null;
+            if (row>=height) return null;
+            return cells[col][row];
+        }
+
+        public PhysicalDevice(final Fpslic fpslic, int width, int height) {
+            this.fpslic = fpslic;
+            this.width = width;
+            this.height = height;
+            sectorWires = new PhysicalNet[width][height][5][2];
+            for(int x=0; x<width; x+=4)
+                for(int y=0; y<height; y+=4)
+                    for(int p=0; p<5; p++) {
+                        for(int xc=x; xc<x+4; xc++) {
+                            PhysicalNet vwire = new PhysicalNet("("+xc+","+y+"-"+(y+3)+")");
+                            for(int yc=y; yc<y+4; yc++)
+                                sectorWires[xc][yc][p][0] = vwire;
+                        }
+                        for(int yc=y; yc<y+4; yc++) {
+                            PhysicalNet hwire = new PhysicalNet("("+x+"-"+(x+3)+","+yc+")");
+                            for(int xc=x; xc<x+4; xc++)
+                                sectorWires[xc][yc][p][1] = hwire;
+                        }
+                    }
+
+            for(int x=4; x<width; x+=4) {
+                for(int y=0; y<height; y++) {
+                    for(int p=0; p<5; p++) {
+                        final int xc = x;
+                        final int yc = y;
+                        final int pc = p;
+                        new PhysicalPip("xxx",
+                                        sectorWires[x-1][y][p][1],
+                                        new PhysicalNet[] { sectorWires[x][y][p][1] },
+                                        5) {
+                            public void set(boolean connected) {
+                                fpslic.cell(xc-1, yc).hwire(pc).drives(fpslic.cell(xc, yc).hwire(pc), connected);
+                            }
+                        };
+                        new PhysicalPip("xxx",
+                                        sectorWires[x][y][p][1],
+                                        new PhysicalNet[] { sectorWires[x-1][y][p][1] },
+                                        5) {
+                            public void set(boolean connected) {
+                                fpslic.cell(xc, yc).hwire(pc).drives(fpslic.cell(xc-1, yc).hwire(pc), connected);
+                            }
+                        };
+                    }
+                }
+            }
+
+            for(int x=0; x<width; x++) {
+                for(int y=4; y<height; y+=4) {
+                    for(int p=0; p<5; p++) {
+                        final int xc = x;
+                        final int yc = y;
+                        final int pc = p;
+                        new PhysicalPip("xxx",
+                                        sectorWires[x][y-1][p][0],
+                                        new PhysicalNet[] { sectorWires[x][y][p][0] },
+                                        5) {
+                            public void set(boolean connected) {
+                                fpslic.cell(xc, yc-1).vwire(pc).drives(fpslic.cell(xc, yc).vwire(pc), connected);
+                            }
+                        };
+                        new PhysicalPip("xxx",
+                                        sectorWires[x][y][p][0],
+                                        new PhysicalNet[] { sectorWires[x][y-1][p][0] },
+                                        5) {
+                            public void set(boolean connected) {
+                                fpslic.cell(xc, yc).vwire(pc).drives(fpslic.cell(xc, yc-1).vwire(pc), connected);
+                            }
+                        };
+                    }
+                }
+            }
+
+            cells = new PhysicalCell[width][height];
+            for(int x=0; x<width; x++)
+                for(int y=0; y<height; y++) {
+                    cells[x][y] = new PhysicalCell(x, y);
+                }
+            for(int x=0; x<width; x++)
+                for(int y=0; y<height; y++)
+                    cells[x][y].link();
+        }
+
+        private PhysicalNet getSectorWire(int col, int row, int plane, boolean horizontal) {
+            return sectorWires[col][row][plane][horizontal ? 1 : 0];
+        }
+
+        public class PhysicalCell {
+
+            public PhysicalNet getNet(String name) {
+                if (name.equals("out")) return outputNet;
+                if (name.equals("xi"))  return xin;
+                if (name.equals("yi"))  return yin;
+                throw new RuntimeException("unknown");
+            }
+
+            private int col;
+            private int row;
+            private PhysicalNet   outputNet;
+            private PhysicalNet   xin;
+            private PhysicalNet   yin;
+            private PhysicalNet[] local = new PhysicalNet[5];
+
+            private Fpslic.Cell cell() { return fpslic.cell(col, row); }
+
+            public void setFunction(String type) {
+                Fpslic.Cell cell = cell();
+                cell.c(XLUT);
+                cell.xo(false);
+                cell.b(false);
+                cell.f(false);
+                if      (type.equals("and2"))    cell.xlut(LUT_SELF & LUT_OTHER);
+                else if (type.equals("or2"))     cell.xlut(LUT_SELF | LUT_OTHER);
+                else if (type.equals("xor2"))    cell.xlut(LUT_SELF ^ LUT_OTHER);
+                else if (type.equals("buf"))     cell.xlut(LUT_SELF);
+                else if (type.equals("inv"))     cell.xlut(~LUT_SELF);
+            }
+
+            public void link() {
+                // FIXME wow, this is a horrendous hack!
+                if (getCell(col-1, row+1) != null)
+                    new PhysicalPip(this+".xiNW", getCell(col-1, row+1).getNet("out"), new PhysicalNet[] { xin }, 5) {
+                        public void set(boolean connected) { cell().xi(connected ? NW : NONE); }
+                    };
+                if (getCell(col-1, row-1) != null)
+                    new PhysicalPip(this+".xiSW", getCell(col-1, row-1).getNet("out"), new PhysicalNet[] { xin }, 5) {
+                        public void set(boolean connected) { cell().xi(connected ? SW : NONE); }
+                    };
+                if (getCell(col+1, row+1) != null)
+                    new PhysicalPip(this+".xiNE", getCell(col+1, row+1).getNet("out"), new PhysicalNet[] { xin }, 5) {
+                        public void set(boolean connected) { cell().xi(connected ? NE : NONE); }
+                    };
+                if (getCell(col+1, row-1) != null)
+                    new PhysicalPip(this+".xiSE", getCell(col+1, row-1).getNet("out"), new PhysicalNet[] { xin }, 5) {
+                        public void set(boolean connected) { cell().xi(connected ? SE : NONE); }
+                    };
+            }
+
+            private PhysicalCell(int col, int row) {
+                this.row = row;
+                this.col = col;
+                outputNet = new PhysicalNet(this.toString()+".out");
+                xin       = new PhysicalNet(this.toString()+".xi");
+                yin       = new PhysicalNet(this.toString()+".yi");
+                for(int j=0; j<5; j++) {
+
+                    // plane 3 is reserved for debugging
+                    if (j==3) continue;
+
+                    final int i = j;
+                    local[i] = new PhysicalNet(this.toString()+".L"+i);
+                    new PhysicalPip(this+".h"+i,  null,      new PhysicalNet[] { local[i], getSectorWire(col, row, i, true) }) {
+                        public void set(boolean connected) { cell().h(i, connected); }
+                    };
+                    new PhysicalPip(this+".v"+i,  null,      new PhysicalNet[] { local[i], getSectorWire(col, row, i, false) }) {
+                        public void set(boolean connected) { cell().v(i, connected); }
+                    };
+                    new PhysicalPip(this+".xi"+i, local[i],  new PhysicalNet[] { xin }) {
+                        public void set(boolean connected) { cell().xi(connected ? i : NONE); }
+                    };
+                    new PhysicalPip(this+".yi"+i, local[i],  new PhysicalNet[] { yin }) {
+                        public void set(boolean connected) { cell().yi(connected ? i : NONE); }
+                    };
+                    new PhysicalPip(this+".o"+i,  outputNet, new PhysicalNet[] { local[i] }) {
+                        public void set(boolean connected) { cell().out(i, connected); }
+                    };
+                }
+            }
+            public  String toString() { return "cell@("+col+","+row+")"; }
+
+        }
+
+        public void route(PhysicalNet source, PhysicalNet[] dests) {
+            HashSet<PhysicalNet> remainingDests = new HashSet<PhysicalNet>();
+            for(PhysicalNet dest : dests) remainingDests.add(dest);
+
+            HashSet<PhysicalNet> needsReset = new HashSet<PhysicalNet>();
+            PriorityQueue<PhysicalNet> pq = new PriorityQueue<PhysicalNet>();
+            needsReset.add(source);
+            source.distance = 0;
+            pq.add(source);
+
+            OUTER: while(true) {
+                PhysicalNet pn = pq.poll();
+                if (pn==null) throw new Error("unroutable! " + source + " -> " + dests[0]);
+                double frontier = pn.distance;
+                for(PhysicalPip pip : pn)
+                    for(PhysicalNet net : pip.getDrivenNets()) {
+                        double newfrontier = frontier + (1/*pip.getCost(pn, net)*/ * (1.0+net.congestion));
+
+                        if (net.load >= 1) newfrontier = newfrontier + 200;
+
+                        if (net.distance <= newfrontier) continue;
+                        pq.remove(net);  // if already in there
+                        net.distance = newfrontier;
+                        pq.add(net);
+                        needsReset.add(net);
+                        net.backpointer = pn;
+                        if (remainingDests.contains(net)) {
+                            remainingDests.remove(net);
+                            if (remainingDests.size()==0) break OUTER;
+                        }
+                    }
+            }
+
+            for(PhysicalNet dest : dests) {
+                PhysicalNet pn = dest;
+                while(pn != null && pn.backpointer != null) {
+                    if (pn.distance != Double.MAX_VALUE) {
+                        pn.distance = Double.MAX_VALUE;
+                        pn.load++;
+                    }
+                    PhysicalPip pip = pn.getPipFrom(pn.backpointer);
+                    pip.set(true);
+                    pn = pn.backpointer;
+                }
+                // FIXME: check pn==source at this point
+            }
+
+            for(PhysicalNet pn : needsReset) {
+                pn.distance    = Double.MAX_VALUE;
+                pn.backpointer = null;
+            }
+        }
+        public HashSet<PhysicalNet> allPhysicalNets = new HashSet<PhysicalNet>();
+        public class PhysicalNet implements Iterable<PhysicalPip>, Comparable<PhysicalNet> {
+            public double      congestion = 0;
+            public int         load = 0;
+            public double      distance = Double.MAX_VALUE;
+            public PhysicalNet backpointer = null;
+
+            public int compareTo(PhysicalNet pn) {
+                double x = distance - pn.distance;
+                return distance > pn.distance
+                    ? 1
+                    : distance < pn.distance
+                    ? -1
+                    : 0;
+            }
+
+            private final HashSet<PhysicalPip> pips = new HashSet<PhysicalPip>();
+            public Iterator<PhysicalPip> iterator() { return pips.iterator(); }
+            private String name;
+            public PhysicalNet(String name) {
+                this.name = name;
+                allPhysicalNets.add(this);
+            }
+            public String toString() { return name; }
+            private void addPip(PhysicalPip pip) { pips.add(pip); }
+            public PhysicalPip getPipFrom(PhysicalNet pn) {
+                for(PhysicalPip pip : pn)
+                    for(PhysicalNet pn2 : pip.getDrivenNets())
+                        if (pn2==this)
+                            return pip;
+                return null;
+            }
+        }
+        
+        public abstract class PhysicalPip {
+            private PhysicalNet   driver;
+            private PhysicalNet[] driven;
+            private String name;
+            private int defaultCost;
+            public String toString() { return name; }
+            public PhysicalNet   getDriverNet()  { return driver; }
+            public PhysicalNet[] getDrivenNets() { return driven; }
+            public int           getCost(PhysicalNet in, PhysicalNet out) { return defaultCost; }
+            public PhysicalPip(String name, PhysicalNet driver, PhysicalNet[] driven) { this(name, driver, driven, 100); }
+            public PhysicalPip(String name, PhysicalNet driver, PhysicalNet[] driven, int defaultCost) {
+                this.name = name;
+                this.driver = driver;
+                this.driven = driven;
+                this.defaultCost = defaultCost;
+                if (driver != null) driver.addPip(this);
+                for(PhysicalNet pn : driven) pn.addPip(this);
+            }
+            public abstract void set(boolean connected);
+        }
+        
+    }
+
+    private static int ret;
+    public static synchronized int scan(final Fpslic device, final Fpslic.Cell cell) {
+        try {
+            scan(device, cell, YLUT, true);
+            ((FtdiBoard)device).readBus(new FtdiBoard.ByteCallback() {
+                    public void call(byte b) throws Exception {
+                        ret = b;
+                        synchronized(device) {
+                            device.notifyAll();
+                        }
+                    }
+                });
+            synchronized(device) {
+                try {
+                    device.wait();
+                } catch (Exception e) { throw new RuntimeException(e); }
+            }
+            scan(device, cell, YLUT, false);
+            return ret;
+        } catch (Exception e) { throw new RuntimeException(e); }
+    }
+
+    public static void scan(Fpslic dev, Fpslic.Cell cell, int source, boolean setup) {
+        if (setup) {
+            //if (source != NONE) cell.c(source);
+            if (cell.b()) cell.b(false);
+            if (cell.f()) cell.f(false);
+        }
+        if (cell.out(L3)!=setup) cell.out(L3, setup);
+        if (cell.vx(L3)!=setup) cell.v(L3, setup);
+
+        Fpslic.SectorWire sw = cell.vwire(L3);
+        //System.out.println("wire is: " + sw);
+
+        if (sw.row > (12 & ~0x3) && sw.north()!=null && sw.north().drives(sw))
+            sw.north().drives(sw, false);
+        while(sw.row > (12 & ~0x3) && sw.south() != null) {
+            //System.out.println(sw + " -> " + sw.south());
+            if (sw.drives(sw.south())!=setup) sw.drives(sw.south(), setup);
+            sw = sw.south();
+        }
+        if (sw.row < (12 & ~0x3) && sw.south() != null && sw.south().drives(sw))
+            sw.north().drives(sw, false);
+        while(sw.row < (12 & ~0x3) && sw.north() != null) {
+            //System.out.println(sw + " -> " + sw.north());
+            if (sw.drives(sw.north())!=setup) sw.drives(sw.north(), setup);
+            sw = sw.north();
+        }
+
+        //cell = dev.cell(19, 15);
+        cell = dev.cell(cell.col, 15);
+        /*
+        System.out.println("cell is " + cell);
+        cell.xlut(0xff);
+        cell.ylut(0xff);
+        cell.b(false);
+        cell.f(false);
+        cell.c(XLUT);
+        cell.out(L3, true);
+        cell.oe(NONE);
+        */
+        if (cell.hx(L3) != setup) cell.h(L3, setup);
+        if (cell.vx(L3) != setup) cell.v(L3, setup);
+        sw = cell.hwire(L3);
+
+        if (sw.west()!=null && sw.west().drives(sw)) { sw.west().drives(sw, false); }
+        while(sw.east() != null) {
+            //System.out.println(sw + " -> " + sw.east());
+            if (sw.drives(sw.east())!=setup) sw.drives(sw.east(), setup);
+            sw = sw.east();
+        }
+
+    }
+
+        public static void setInput(FlatNetlist fnl, Fpslic fpslic, String prefix, int val) {
+            for(int i=0; ; i++) {
+                FlatNetlist.Node n = fnl.top.get(prefix + "["+i+"]");
+                if (n==null && i==0) n = fnl.top.get(prefix);
+                if (n==null) return;
+                Fpslic.Cell c = n.getPlacement(fpslic);
+                c.c(XLUT);
+                c.b(false);
+                c.xlut((val & 0x1)==0 ? 0x00 : 0xff);
+                val = val >> 1;
+            }
+        }
+        public static int getOutput(FlatNetlist fnl, Fpslic fpslic, String prefix) {
+            int val = 0;
+            for(int i=0; ; i++) {
+                FlatNetlist.Node n = fnl.top.get(prefix+"["+i+"]");
+                if (n==null && i==0) n = fnl.top.get(prefix);
+                if (n==null) return val;
+                Fpslic.Cell c = n.getPlacement(fpslic);
+                c.xlut(LUT_SELF);
+                c.c(XLUT);
+                c.b(false);
+                fpslic.flush();
+                int scan = scan(fpslic, c);
+                val |= ((scan==0 ? 0 : 1) << i);
+            }
+        }
+
+
+}
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