rr_graph_timing_params.c

VPR布局布线源码

#include <assert.h>
#include "util.h"
#include "vpr_types.h"
#include "globals.h"
#include "rr_graph.h"
#include "rr_graph_util.h"
#include "rr_graph2.h"
#include "rr_graph_timing_params.h"



/****************** Subroutine definitions *********************************/


void
add_rr_graph_C_from_switches(float C_ipin_cblock)
{

/* This routine finishes loading the C elements of the rr_graph. It assumes *
 * that when you call it the CHANX and CHANY nodes have had their C set to  *
 * their metal capacitance, and everything else has C set to 0.  The graph  *
 * connectivity (edges, switch types etc.) must all be loaded too.  This    *
 * routine will add in the capacitance on the CHANX and CHANY nodes due to: *
 *                                                                          *
 * 1) The output capacitance of the switches coming from OPINs;             *
 * 2) The input and output capacitance of the switches between the various  *
 *    wiring (CHANX and CHANY) segments; and                                *
 * 3) The input capacitance of the buffers separating routing tracks from   *
 *    the connection block inputs.                                          */


    int inode, iedge, switch_index, to_node, maxlen;
    int icblock, isblock, iseg_low, iseg_high;
    float Cin, Cout;
    t_rr_type from_rr_type, to_rr_type;
    boolean *cblock_counted;	/* [0..max(nx,ny)] -- 0th element unused. */
    float *buffer_Cin;		/* [0..max(nx,ny)] */
    boolean buffered;
    float *Couts_to_add;	/* UDSD */

    maxlen = max(nx, ny) + 1;
    cblock_counted = (boolean *) my_calloc(maxlen, sizeof(boolean));
    buffer_Cin = (float *)my_calloc(maxlen, sizeof(float));

    for(inode = 0; inode < num_rr_nodes; inode++)
	{

	    from_rr_type = rr_node[inode].type;

	    if(from_rr_type == CHANX || from_rr_type == CHANY)
		{

		    for(iedge = 0; iedge < rr_node[inode].num_edges; iedge++)
			{

			    to_node = rr_node[inode].edges[iedge];
			    to_rr_type = rr_node[to_node].type;

			    if(to_rr_type == CHANX || to_rr_type == CHANY)
				{

				    switch_index =
					rr_node[inode].switches[iedge];
				    Cin = switch_inf[switch_index].Cin;
				    Cout = switch_inf[switch_index].Cout;
				    buffered =
					switch_inf[switch_index].buffered;

				    /* If both the switch from inode to to_node and the switch from *
				     * to_node back to inode use bidirectional switches (i.e. pass  *
				     * transistors), there will only be one physical switch for     *
				     * both edges.  Hence, I only want to count the capacitance of  *
				     * that switch for one of the two edges.  (Note:  if there is   *
				     * a pass transistor edge from x to y, I always build the graph *
				     * so that there is a corresponding edge using the same switch  *
				     * type from y to x.) So, I arbitrarily choose to add in the    *
				     * capacitance in that case of a pass transistor only when      *
				     * processing the the lower inode number.                       *
				     * If an edge uses a buffer I always have to add in the output  *
				     * capacitance.  I assume that buffers are shared at the same   *
				     * (i,j) location, so only one input capacitance needs to be    *
				     * added for all the buffered switches at that location.  If    *
				     * the buffers at that location have different sizes, I use the *
				     * input capacitance of the largest one.                        */

				    if(!buffered && inode < to_node)
					{	/* Pass transistor. */
					    rr_node[inode].C += Cin;
					    rr_node[to_node].C += Cout;
					}

				    else if(buffered)
					{
					    /* Prevent double counting of capacitance for UDSD */
					    if(rr_node[to_node].drivers !=
					       SINGLE)
						{
						    /* For multiple-driver architectures the output capacitance can
						     * be added now since each edge is actually a driver */
						    rr_node[to_node].C +=
							Cout;
						}
					    isblock =
						seg_index_of_sblock(inode,
								    to_node);
					    buffer_Cin[isblock] =
						max(buffer_Cin[isblock], Cin);
					}

				}
			    /* End edge to CHANX or CHANY node. */
			    else if(to_rr_type == IPIN)
				{

				    /* Code below implements sharing of the track to connection     *
				     * box buffer.  I assume there is one such buffer at every      *
				     * segment of the wire at which at least one logic block input  *
				     * connects.                                                    */

				    icblock =
					seg_index_of_cblock(from_rr_type,
							    to_node);
				    if(cblock_counted[icblock] == FALSE)
					{
					    rr_node[inode].C += C_ipin_cblock;
					    cblock_counted[icblock] = TRUE;
					}
				}
			}	/* End loop over all edges of a node. */

		    /* Reset the cblock_counted and buffer_Cin arrays, and add buf Cin. */

		    /* Method below would be faster for very unpopulated segments, but I  *
		     * think it would be slower overall for most FPGAs, so commented out. */

		    /*   for (iedge=0;iedge<rr_node[inode].num_edges;iedge++) {
		     * to_node = rr_node[inode].edges[iedge];
		     * if (rr_node[to_node].type == IPIN) {
		     * icblock = seg_index_of_cblock (from_rr_type, to_node);
		     * cblock_counted[icblock] = FALSE;
		     * }
		     * }     */

		    if(from_rr_type == CHANX)
			{
			    iseg_low = rr_node[inode].xlow;
			    iseg_high = rr_node[inode].xhigh;
			}
		    else
			{	/* CHANY */
			    iseg_low = rr_node[inode].ylow;
			    iseg_high = rr_node[inode].yhigh;
			}

		    for(icblock = iseg_low; icblock <= iseg_high; icblock++)
			{
			    cblock_counted[icblock] = FALSE;
			}

		    for(isblock = iseg_low - 1; isblock <= iseg_high;
			isblock++)
			{
			    rr_node[inode].C += buffer_Cin[isblock];	/* Biggest buf Cin at loc */
			    buffer_Cin[isblock] = 0.;
			}

		}
	    /* End node is CHANX or CHANY */
	    else if(from_rr_type == OPIN)
		{

		    for(iedge = 0; iedge < rr_node[inode].num_edges; iedge++)
			{
			    switch_index = rr_node[inode].switches[iedge];
			    /* UDSD by ICK Start */
			    to_node = rr_node[inode].edges[iedge];
			    to_rr_type = rr_node[to_node].type;
			    assert(to_rr_type == CHANX
				   || to_rr_type == CHANY);
			    if(rr_node[to_node].drivers != SINGLE)
				{
				    Cout = switch_inf[switch_index].Cout;
				    to_node = rr_node[inode].edges[iedge];	/* Will be CHANX or CHANY */
				    rr_node[to_node].C += Cout;
				}
			}
		}
	    /* End node is OPIN. */
	}			/* End for all nodes. */

    /* Now we need to add any cout loads for nets that we previously didn't process
     * Current structures only keep switch information from a node to the next node and
     * not the reverse.  Therefore I need to go through all the possible edges to figure 
     * out what the Cout's should be */
    Couts_to_add = (float *)my_calloc(num_rr_nodes, sizeof(float));
    for(inode = 0; inode < num_rr_nodes; inode++)
	{
	    for(iedge = 0; iedge < rr_node[inode].num_edges; iedge++)
		{
		    switch_index = rr_node[inode].switches[iedge];
		    to_node = rr_node[inode].edges[iedge];
		    to_rr_type = rr_node[to_node].type;
		    if(to_rr_type == CHANX || to_rr_type == CHANY)
			{
			    if(rr_node[to_node].drivers == SINGLE)
				{
				    /* Cout was not added in these cases */
				    if(Couts_to_add[to_node] != 0)
					{
					    /* We've already found a Cout to add to this node
					     * We could take the max of all possibilities but
					     * instead I will fail if there are conflicting Couts */
					    if(Couts_to_add[to_node] !=
					       switch_inf[switch_index].Cout)
						{
						    printf
							("Error: A single driver resource (%i) is driven by different Cout's (%e!=%e)\n",
							 to_node,
							 Couts_to_add
							 [to_node],
							 switch_inf
							 [switch_index].Cout);
						    exit(1);
						}
					}
				    Couts_to_add[to_node] =
					switch_inf[switch_index].Cout;

				}
			}
		}
	}
    for(inode = 0; inode < num_rr_nodes; inode++)
	{
	    rr_node[inode].C += Couts_to_add[inode];
	}
    free(Couts_to_add);
    free(cblock_counted);
    free(buffer_Cin);
}