rr_graph_indexed_data.c

用于学术研究的FPGA布局布线软件VPR

#include <math.h>		/* Needed only for sqrt call (remove if sqrt removed) */
#include "util.h"
#include "vpr_types.h"
#include "globals.h"
#include "rr_graph_util.h"
#include "rr_graph2.h"
#include "rr_graph_indexed_data.h"


/******************* Subroutines local to this module ************************/

static void load_rr_indexed_data_base_costs(int nodes_per_chan,
					    t_ivec *** rr_node_indices,
					    enum e_base_cost_type
					    base_cost_type,
					    int wire_to_ipin_switch);

static float get_delay_normalization_fac(int nodes_per_chan,
					 t_ivec *** rr_node_indices);

static float get_average_opin_delay(t_ivec *** rr_node_indices,
				    int nodes_per_chan);

static void load_rr_indexed_data_T_values(int index_start,
					  int num_indices_to_load,
					  t_rr_type rr_type,
					  int nodes_per_chan,
					  t_ivec *** rr_node_indices,
					  t_segment_inf * segment_inf);



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

/* Allocates the rr_indexed_data array and loads it with appropriate values. *
 * It currently stores the segment type (or OPEN if the index doesn't        *
 * correspond to an CHANX or CHANY type), the base cost of nodes of that     *
 * type, and some info to allow rapid estimates of time to get to a target   *
 * to be computed by the router.                                             *
 *
 * Right now all SOURCES have the same base cost; and similarly there's only *
 * one base cost for each of SINKs, OPINs, and IPINs (four total).  This can *
 * be changed just by allocating more space in the array below and changing  *
 * the cost_index values for these rr_nodes, if you want to make some pins   *
 * etc. more expensive than others.  I give each segment type in an          *
 * x-channel its own cost_index, and each segment type in a y-channel its    *
 * own cost_index.                                                           */
void
alloc_and_load_rr_indexed_data(IN t_segment_inf * segment_inf,
			       IN int num_segment,
			       IN t_ivec *** rr_node_indices,
			       IN int nodes_per_chan,
			       int wire_to_ipin_switch,
			       enum e_base_cost_type base_cost_type)
{

    int iseg, length, i, index;

    num_rr_indexed_data = CHANX_COST_INDEX_START + (2 * num_segment);
    rr_indexed_data = (t_rr_indexed_data *) my_malloc(num_rr_indexed_data *
						      sizeof
						      (t_rr_indexed_data));

    /* For rr_types that aren't CHANX or CHANY, base_cost is valid, but most     *
     * * other fields are invalid.  For IPINs, the T_linear field is also valid;   *
     * * all other fields are invalid.  For SOURCES, SINKs and OPINs, all fields   *
     * * other than base_cost are invalid. Mark invalid fields as OPEN for safety. */

    for(i = SOURCE_COST_INDEX; i <= IPIN_COST_INDEX; i++)
	{
	    rr_indexed_data[i].ortho_cost_index = OPEN;
	    rr_indexed_data[i].seg_index = OPEN;
	    rr_indexed_data[i].inv_length = OPEN;
	    rr_indexed_data[i].T_linear = OPEN;
	    rr_indexed_data[i].T_quadratic = OPEN;
	    rr_indexed_data[i].C_load = OPEN;
	}

    rr_indexed_data[IPIN_COST_INDEX].T_linear =
	switch_inf[wire_to_ipin_switch].Tdel;

    /* X-directed segments. */

    for(iseg = 0; iseg < num_segment; iseg++)
	{
	    index = CHANX_COST_INDEX_START + iseg;

	    rr_indexed_data[index].ortho_cost_index = index + num_segment;

	    if(segment_inf[iseg].longline)
		length = nx;
	    else
		length = min(segment_inf[iseg].length, nx);


	    rr_indexed_data[index].inv_length = 1. / length;
	    rr_indexed_data[index].seg_index = iseg;
	}

    load_rr_indexed_data_T_values(CHANX_COST_INDEX_START, num_segment,
				  CHANX, nodes_per_chan, rr_node_indices,
				  segment_inf);

    /* Y-directed segments. */

    for(iseg = 0; iseg < num_segment; iseg++)
	{
	    index = CHANX_COST_INDEX_START + num_segment + iseg;

	    rr_indexed_data[index].ortho_cost_index = index - num_segment;

	    if(segment_inf[iseg].longline)
		length = ny;
	    else
		length = min(segment_inf[iseg].length, ny);

	    rr_indexed_data[index].inv_length = 1. / length;
	    rr_indexed_data[index].seg_index = iseg;
	}

    load_rr_indexed_data_T_values((CHANX_COST_INDEX_START + num_segment),
				  num_segment, CHANY, nodes_per_chan,
				  rr_node_indices, segment_inf);

    load_rr_indexed_data_base_costs(nodes_per_chan, rr_node_indices,
				    base_cost_type, wire_to_ipin_switch);

}


static void
load_rr_indexed_data_base_costs(int nodes_per_chan,
				t_ivec *** rr_node_indices,
				enum e_base_cost_type base_cost_type,
				int wire_to_ipin_switch)
{

/* Loads the base_cost member of rr_indexed_data according to the specified *
 * base_cost_type.                                                          */

    float delay_normalization_fac;
    int index;

    if(base_cost_type == DELAY_NORMALIZED)
	{
	    delay_normalization_fac =
		get_delay_normalization_fac(nodes_per_chan, rr_node_indices);
	}
    else
	{
	    delay_normalization_fac = 1.;
	}

    if(base_cost_type == DEMAND_ONLY || base_cost_type == DELAY_NORMALIZED)
	{
	    rr_indexed_data[SOURCE_COST_INDEX].base_cost =
		delay_normalization_fac;
	    rr_indexed_data[SINK_COST_INDEX].base_cost = 0.;
	    rr_indexed_data[OPIN_COST_INDEX].base_cost =
		delay_normalization_fac;

#ifndef SPEC
	    rr_indexed_data[IPIN_COST_INDEX].base_cost =
		0.95 * delay_normalization_fac;
#else /* Avoid roundoff for SPEC */
	    rr_indexed_data[IPIN_COST_INDEX].base_cost =
		delay_normalization_fac;
#endif
	}

    else if(base_cost_type == INTRINSIC_DELAY)
	{
	    rr_indexed_data[SOURCE_COST_INDEX].base_cost = 0.;
	    rr_indexed_data[SINK_COST_INDEX].base_cost = 0.;
	    rr_indexed_data[OPIN_COST_INDEX].base_cost =
		get_average_opin_delay(rr_node_indices, nodes_per_chan);
	    rr_indexed_data[IPIN_COST_INDEX].base_cost =
		switch_inf[wire_to_ipin_switch].Tdel;
	}

/* Load base costs for CHANX and CHANY segments */

    for(index = CHANX_COST_INDEX_START; index < num_rr_indexed_data; index++)
	{
	    if(base_cost_type == INTRINSIC_DELAY)
		rr_indexed_data[index].base_cost =
		    rr_indexed_data[index].T_linear +
		    rr_indexed_data[index].T_quadratic;
	    else
/*       rr_indexed_data[index].base_cost = delay_normalization_fac /
                                    rr_indexed_data[index].inv_length;  */

		rr_indexed_data[index].base_cost = delay_normalization_fac;
/*       rr_indexed_data[index].base_cost = delay_normalization_fac *
                  sqrt (1. / rr_indexed_data[index].inv_length);  */
/*       rr_indexed_data[index].base_cost = delay_normalization_fac *
                  (1. + 1. / rr_indexed_data[index].inv_length);  */
	}

/* Save a copy of the base costs -- if dynamic costing is used by the     * 
 * router, the base_cost values will get changed all the time and being   *
 * able to restore them from a saved version is useful.                   */

    for(index = 0; index < num_rr_indexed_data; index++)
	{
	    rr_indexed_data[index].saved_base_cost =
		rr_indexed_data[index].base_cost;
	}
}


static float
get_delay_normalization_fac(int nodes_per_chan,
			    t_ivec *** rr_node_indices)
{

/* Returns the average delay to go 1 FB distance along a wire.  */

    const int clb_dist = 3;	/* Number of CLBs I think the average conn. goes. */

    int inode, itrack, cost_index;
    float Tdel, Tdel_sum, frac_num_seg;

    Tdel_sum = 0.;

    for(itrack = 0; itrack < nodes_per_chan; itrack++)
	{
	    inode =
		get_rr_node_index((nx + 1) / 2, (ny + 1) / 2, CHANX, itrack,
				  rr_node_indices);
	    cost_index = rr_node[inode].cost_index;
	    frac_num_seg = clb_dist * rr_indexed_data[cost_index].inv_length;
	    Tdel = frac_num_seg * rr_indexed_data[cost_index].T_linear +
		frac_num_seg * frac_num_seg *
		rr_indexed_data[cost_index].T_quadratic;
	    Tdel_sum += Tdel / (float)clb_dist;
	}

    for(itrack = 0; itrack < nodes_per_chan; itrack++)
	{
	    inode =
		get_rr_node_index((nx + 1) / 2, (ny + 1) / 2, CHANY, itrack,
				  rr_node_indices);
	    cost_index = rr_node[inode].cost_index;
	    frac_num_seg = clb_dist * rr_indexed_data[cost_index].inv_length;
	    Tdel = frac_num_seg * rr_indexed_data[cost_index].T_linear +
		frac_num_seg * frac_num_seg *
		rr_indexed_data[cost_index].T_quadratic;
	    Tdel_sum += Tdel / (float)clb_dist;
	}

    return (Tdel_sum / (2. * nodes_per_chan));
}


static float
get_average_opin_delay(t_ivec *** rr_node_indices,
		       int nodes_per_chan)
{

/* Returns the average delay from an OPIN to a wire in an adjacent channel. */
    /* RESEARCH TODO: Got to think if this heuristic needs to change for hetero, right now, I'll calculate
     * the average delay of non-IO blocks */
    int inode, ipin, iclass, iedge, itype, num_edges, to_switch, to_node,
	num_conn;
    float Cload, Tdel;

    Tdel = 0.;
    num_conn = 0;
    for(itype = 0;
	itype < num_types && &type_descriptors[itype] != IO_TYPE; itype++)
	{
	    for(ipin = 0; ipin < type_descriptors[itype].num_pins; ipin++)
		{
		    iclass = type_descriptors[itype].pin_class[ipin];
		    if(type_descriptors[itype].class_inf[iclass].type ==
		       DRIVER)
			{	/* OPIN */
			    inode =
				get_rr_node_index((nx + 1) / 2, (ny + 1) / 2,
						  OPIN, ipin,
						  rr_node_indices);
			    num_edges = rr_node[inode].num_edges;

			    for(iedge = 0; iedge < num_edges; iedge++)
				{
				    to_node = rr_node[inode].edges[iedge];
				    to_switch =
					rr_node[inode].switches[iedge];
				    Cload = rr_node[to_node].C;
				    Tdel +=
					Cload * switch_inf[to_switch].R +
					switch_inf[to_switch].Tdel;
				    num_conn++;
				}
			}
		}
	}

    Tdel /= (float)num_conn;
    return (Tdel);
}


static void
load_rr_indexed_data_T_values(int index_start,
			      int num_indices_to_load,
			      t_rr_type rr_type,
			      int nodes_per_chan,
			      t_ivec *** rr_node_indices,
			      t_segment_inf * segment_inf)
{

/* Loads the average propagation times through segments of each index type  *
 * for either all CHANX segment types or all CHANY segment types.  It does  *
 * this by looking at all the segments in one channel in the middle of the  *
 * array and averaging the R and C values of all segments of the same type  *
 * and using them to compute average delay values for this type of segment. */

    int itrack, iseg, inode, cost_index, iswitch;
    float *C_total, *R_total;	/* [0..num_rr_indexed_data - 1] */
    int *num_nodes_of_index;	/* [0..num_rr_indexed_data - 1] */
    float Rnode, Cnode, Rsw, Tsw;

    num_nodes_of_index = (int *)my_calloc(num_rr_indexed_data, sizeof(int));
    C_total = (float *)my_calloc(num_rr_indexed_data, sizeof(float));
    R_total = (float *)my_calloc(num_rr_indexed_data, sizeof(float));

/* Get average C and R values for all the segments of this type in one      *
 * channel segment, near the middle of the array.                           */

    for(itrack = 0; itrack < nodes_per_chan; itrack++)
	{
	    inode =
		get_rr_node_index((nx + 1) / 2, (ny + 1) / 2, rr_type, itrack,
				  rr_node_indices);
	    cost_index = rr_node[inode].cost_index;
	    num_nodes_of_index[cost_index]++;
	    C_total[cost_index] += rr_node[inode].C;
	    R_total[cost_index] += rr_node[inode].R;
	}


    for(cost_index = index_start;
	cost_index < index_start + num_indices_to_load; cost_index++)
	{

	    if(num_nodes_of_index[cost_index] == 0)
		{		/* Segments don't exist. */
		    rr_indexed_data[cost_index].T_linear = OPEN;
		    rr_indexed_data[cost_index].T_quadratic = OPEN;
		    rr_indexed_data[cost_index].C_load = OPEN;
		}
	    else
		{
		    Rnode =
			R_total[cost_index] / num_nodes_of_index[cost_index];
		    Cnode =
			C_total[cost_index] / num_nodes_of_index[cost_index];
		    iseg = rr_indexed_data[cost_index].seg_index;
		    iswitch = segment_inf[iseg].wire_switch;
		    Rsw = switch_inf[iswitch].R;
		    Tsw = switch_inf[iswitch].Tdel;

		    if(switch_inf[iswitch].buffered)
			{
			    rr_indexed_data[cost_index].T_linear =
				Tsw + Rsw * Cnode + 0.5 * Rnode * Cnode;
			    rr_indexed_data[cost_index].T_quadratic = 0.;
			    rr_indexed_data[cost_index].C_load = 0.;
			}
		    else
			{	/* Pass transistor */
			    rr_indexed_data[cost_index].C_load = Cnode;

			    /* See Dec. 23, 1997 notes for deriviation of formulae. */

			    rr_indexed_data[cost_index].T_linear =
				Tsw + 0.5 * Rsw * Cnode;
			    rr_indexed_data[cost_index].T_quadratic =
				(Rsw + Rnode) * 0.5 * Cnode;
			}
		}
	}

    free(num_nodes_of_index);
    free(C_total);
    free(R_total);
}