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# Authors: Steve Reinhardt

from m5.params import *
from m5.objects import *

from BaseTopology import SimpleTopology

class Crossbar(SimpleTopology):
    description='Crossbar'

    def makeTopology(self, options, IntLink, ExtLink, Router):
        # Create an individual router for each controller plus one more for the
        # centralized crossbar.  The large numbers of routers are needed because
        # external links do not model outgoing bandwidth in the simple network, but
        # internal links do.

        routers = [Router(router_id=i) for i in range(len(self.nodes)+1)]
        ext_links = [ExtLink(link_id=i, ext_node=n, int_node=routers[i])
                        for (i, n) in enumerate(self.nodes)]
        link_count = len(self.nodes)
        xbar = routers[len(self.nodes)] # the crossbar router is the last router created
        int_links = [IntLink(link_id=(link_count+i),
                             node_a=routers[i], node_b=xbar)
                        for i in range(len(self.nodes))]

        return routers, int_links, ext_links
