gem5/ext/mcpat/cacti/component.cc
Anthony Gutierrez e553a7bfa7 ext: add McPAT source
this patch adds the source for mcpat, a power, area, and timing modeling
framework.
2014-04-01 12:44:30 -04:00

236 lines
7.4 KiB
C++

/*****************************************************************************
* McPAT/CACTI
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* Copyright 2012 Hewlett-Packard Development Company, L.P.
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***************************************************************************/
#include <cassert>
#include <cmath>
#include <iostream>
#include "bank.h"
#include "component.h"
#include "decoder.h"
using namespace std;
Component::Component()
:area(), power(), rt_power(),delay(0)
{
}
Component::~Component()
{
}
double Component::compute_diffusion_width(int num_stacked_in, int num_folded_tr)
{
double w_poly = g_ip->F_sz_um;
double spacing_poly_to_poly = g_tp.w_poly_contact + 2 * g_tp.spacing_poly_to_contact;
double total_diff_w = 2 * spacing_poly_to_poly + // for both source and drain
num_stacked_in * w_poly +
(num_stacked_in - 1) * g_tp.spacing_poly_to_poly;
if (num_folded_tr > 1)
{
total_diff_w += (num_folded_tr - 2) * 2 * spacing_poly_to_poly +
(num_folded_tr - 1) * num_stacked_in * w_poly +
(num_folded_tr - 1) * (num_stacked_in - 1) * g_tp.spacing_poly_to_poly;
}
return total_diff_w;
}
double Component::compute_gate_area(
int gate_type,
int num_inputs,
double w_pmos,
double w_nmos,
double h_gate)
{
if (w_pmos <= 0.0 || w_nmos <= 0.0)
{
return 0.0;
}
double w_folded_pmos, w_folded_nmos;
int num_folded_pmos, num_folded_nmos;
double total_ndiff_w, total_pdiff_w;
Area gate;
double h_tr_region = h_gate - 2 * g_tp.HPOWERRAIL;
double ratio_p_to_n = w_pmos / (w_pmos + w_nmos);
if (ratio_p_to_n >= 1 || ratio_p_to_n <= 0)
{
return 0.0;
}
w_folded_pmos = (h_tr_region - g_tp.MIN_GAP_BET_P_AND_N_DIFFS) * ratio_p_to_n;
w_folded_nmos = (h_tr_region - g_tp.MIN_GAP_BET_P_AND_N_DIFFS) * (1 - ratio_p_to_n);
assert(w_folded_pmos > 0);
num_folded_pmos = (int) (ceil(w_pmos / w_folded_pmos));
num_folded_nmos = (int) (ceil(w_nmos / w_folded_nmos));
switch (gate_type)
{
case INV:
total_ndiff_w = compute_diffusion_width(1, num_folded_nmos);
total_pdiff_w = compute_diffusion_width(1, num_folded_pmos);
break;
case NOR:
total_ndiff_w = compute_diffusion_width(1, num_inputs * num_folded_nmos);
total_pdiff_w = compute_diffusion_width(num_inputs, num_folded_pmos);
break;
case NAND:
total_ndiff_w = compute_diffusion_width(num_inputs, num_folded_nmos);
total_pdiff_w = compute_diffusion_width(1, num_inputs * num_folded_pmos);
break;
default:
cout << "Unknown gate type: " << gate_type << endl;
exit(1);
}
gate.w = MAX(total_ndiff_w, total_pdiff_w);
if (w_folded_nmos > w_nmos)
{
//means that the height of the gate can
//be made smaller than the input height specified, so calculate the height of the gate.
gate.h = w_nmos + w_pmos + g_tp.MIN_GAP_BET_P_AND_N_DIFFS + 2 * g_tp.HPOWERRAIL;
}
else
{
gate.h = h_gate;
}
return gate.get_area();
}
double Component::compute_tr_width_after_folding(
double input_width,
double threshold_folding_width)
{//This is actually the width of the cell not the width of a device.
//The width of a cell and the width of a device is orthogonal.
if (input_width <= 0)
{
return 0;
}
int num_folded_tr = (int) (ceil(input_width / threshold_folding_width));
double spacing_poly_to_poly = g_tp.w_poly_contact + 2 * g_tp.spacing_poly_to_contact;
double width_poly = g_ip->F_sz_um;
double total_diff_width = num_folded_tr * width_poly + (num_folded_tr + 1) * spacing_poly_to_poly;
return total_diff_width;
}
double Component::height_sense_amplifier(double pitch_sense_amp)
{
// compute the height occupied by all PMOS transistors
double h_pmos_tr = compute_tr_width_after_folding(g_tp.w_sense_p, pitch_sense_amp) * 2 +
compute_tr_width_after_folding(g_tp.w_iso, pitch_sense_amp) +
2 * g_tp.MIN_GAP_BET_SAME_TYPE_DIFFS;
// compute the height occupied by all NMOS transistors
double h_nmos_tr = compute_tr_width_after_folding(g_tp.w_sense_n, pitch_sense_amp) * 2 +
compute_tr_width_after_folding(g_tp.w_sense_en, pitch_sense_amp) +
2 * g_tp.MIN_GAP_BET_SAME_TYPE_DIFFS;
// compute total height by considering gap between the p and n diffusion areas
return h_pmos_tr + h_nmos_tr + g_tp.MIN_GAP_BET_P_AND_N_DIFFS;
}
int Component::logical_effort(
int num_gates_min,
double g,
double F,
double * w_n,
double * w_p,
double C_load,
double p_to_n_sz_ratio,
bool is_dram_,
bool is_wl_tr_,
double max_w_nmos)
{
int num_gates = (int) (log(F) / log(fopt));
// check if num_gates is odd. if so, add 1 to make it even
num_gates+= (num_gates % 2) ? 1 : 0;
num_gates = MAX(num_gates, num_gates_min);
// recalculate the effective fanout of each stage
double f = pow(F, 1.0 / num_gates);
int i = num_gates - 1;
double C_in = C_load / f;
w_n[i] = (1.0 / (1.0 + p_to_n_sz_ratio)) * C_in / gate_C(1, 0, is_dram_, false, is_wl_tr_);
w_n[i] = MAX(w_n[i], g_tp.min_w_nmos_);
w_p[i] = p_to_n_sz_ratio * w_n[i];
if (w_n[i] > max_w_nmos)
{
double C_ld = gate_C((1 + p_to_n_sz_ratio) * max_w_nmos, 0, is_dram_, false, is_wl_tr_);
F = g * C_ld / gate_C(w_n[0] + w_p[0], 0, is_dram_, false, is_wl_tr_);
num_gates = (int) (log(F) / log(fopt)) + 1;
num_gates+= (num_gates % 2) ? 1 : 0;
num_gates = MAX(num_gates, num_gates_min);
f = pow(F, 1.0 / (num_gates - 1));
i = num_gates - 1;
w_n[i] = max_w_nmos;
w_p[i] = p_to_n_sz_ratio * w_n[i];
}
for (i = num_gates - 2; i >= 1; i--)
{
w_n[i] = MAX(w_n[i+1] / f, g_tp.min_w_nmos_);
w_p[i] = p_to_n_sz_ratio * w_n[i];
}
assert(num_gates <= MAX_NUMBER_GATES_STAGE);
return num_gates;
}