var32 cons(var32 x, var32 y){
    var32 ptr;
    uid id, hashedId;
    map newMap, currentMap;
    u32 colls;

    #ifdef __DEBUG__
    ++consCount;
    colls = 0;
    #endif

    // Before anything, compute the unique id of that node.
    id = (((uid)(x.ptr))<<32) | (uid)y.ptr;

    // Try to find the node. If it already exists, return its ptr.
    hashedId = id % MAP_HASH_SIZE;
    currentMap = mapByHashedId[hashedId];
    if (currentMap) do {
        if (mapId[currentMap] == id)
            return mapPtr[currentMap];
        #ifdef __DEBUG__
        ++colls;
        #endif
    } while ((currentMap = mapNext[currentMap]));

    #ifdef __DEBUG__
    if (colls<16) ++collisionCount[colls];
    ++allocCount;
    #endif

    // If does not exist, then alloc a new ptr to it.
    ptr = nodeNewPtr[nodeNewPtrIndex--];

    // Add that new ptr to the map.
    newMap = mapNewPtr[mapNewPtrIndex--];
    if (mapByHashedId[hashedId])
        mapNext[newMap] = mapByHashedId[hashedId];
    mapId[newMap] = id;
    mapPtr[newMap] = ptr;
    mapByHashedId[hashedId] = newMap;

    // Fill that new ptr.
    nodeLeft[GETPTR(ptr)] = x;
    nodeRight[GETPTR(ptr)] = y;

    return ptr;
};

currentMap = mapByHashedId[hashedId];
if (currentMap) do {
    if (mapId[currentMap] == id)
        return mapPtr[currentMap];
    #ifdef __DEBUG__
    ++colls;
    #endif
} while ((currentMap = mapNext[currentMap]));

currentMap = mapByHashedId[hashedId];
while (currentMap)
{
    if (mapId[currentMap] == id)
        return mapPtr[currentMap];

    #ifdef __DEBUG__
    ++colls;
    #endif

    currentMap = mapNext[currentMap]
}

x      y
---    ---
0x1    0x1
0x2    0x1
0x3    0x1
0x4    0x1

x      y          id   hashedId
---    ---  ----------   --------
0x1    0x1  0x10000001        0x1
0x2    0x1  0x20000001        0x1
0x3    0x1  0x30000001        0x1
0x4    0x1  0x40000001        0x1

hashedId = ((x << 7) ^ (y * 31)) % MAP_HASH_SIZE;