[FPGA-SPICE] Add pass-gate SPICE netlist writer

This commit is contained in:
tangxifan 2020-09-19 14:59:00 -06:00
parent 9e4353ddf4
commit 51d423e4db
3 changed files with 386 additions and 2 deletions

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@ -1,6 +1,6 @@
/************************************************
* This file includes functions on
* outputting Verilog netlists for essential gates
* outputting SPICE netlists for essential gates
* which are inverters, buffers, transmission-gates
* logic gates etc.
***********************************************/
@ -22,6 +22,7 @@
#include "spice_constants.h"
#include "spice_writer_utils.h"
#include "spice_passgate.h"
#include "spice_essential_gates.h"
/* begin namespace openfpga */
@ -1046,7 +1047,7 @@ int print_spice_essential_gates(NetlistManager& netlist_manager,
VTR_ASSERT(TECH_LIB_MODEL_TRANSISTOR == tech_lib.model_type(tech_model));
}
/* Now branch on netlist writing */
/* Now branch on netlist writing: for inverter/buffers */
if (CIRCUIT_MODEL_INVBUF == circuit_lib.model_type(circuit_model)) {
if (CIRCUIT_MODEL_BUF_INV == circuit_lib.buffer_type(circuit_model)) {
VTR_ASSERT(true == module_manager.valid_module_id(module_id));
@ -1069,6 +1070,21 @@ int print_spice_essential_gates(NetlistManager& netlist_manager,
/* Finish, go to the next */
continue;
}
/* Now branch on netlist writing: for inverter/buffers */
if (CIRCUIT_MODEL_PASSGATE == circuit_lib.model_type(circuit_model)) {
status = print_spice_passgate_subckt(fp,
module_manager, module_id,
circuit_lib, circuit_model,
tech_lib, tech_model);
if (CMD_EXEC_FATAL_ERROR == status) {
break;
}
/* Finish, go to the next */
continue;
}
}
/* Close file handler*/

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@ -0,0 +1,338 @@
/************************************************
* This file includes functions on
* outputting SPICE netlists for transmission-gates
***********************************************/
#include <fstream>
#include <cmath>
#include <iomanip>
/* Headers from vtrutil library */
#include "vtr_assert.h"
#include "vtr_log.h"
/* Headers from openfpgashell library */
#include "command_exit_codes.h"
/* Headers from openfpgautil library */
#include "openfpga_digest.h"
#include "circuit_library_utils.h"
#include "spice_constants.h"
#include "spice_writer_utils.h"
#include "spice_passgate.h"
/* begin namespace openfpga */
namespace openfpga {
/********************************************************************
* Generate the SPICE modeling for the PMOS part of a pass-gate logic
*
* This function is created to be shared by pass-transistor and
* transmission-gate SPICE netlist writer
*
* Note:
* - This function does NOT create a file
* but requires a file stream created
* - This function only output SPICE modeling for
* a pass-gate. Any preprocessing or subckt definition should not be included!
*******************************************************************/
static
int print_spice_passgate_pmos_modeling(std::fstream& fp,
const std::string& trans_name_postfix,
const std::string& input_port_name,
const std::string& gate_port_name,
const std::string& output_port_name,
const TechnologyLibrary& tech_lib,
const TechnologyModelId& tech_model,
const float& trans_width) {
if (false == valid_file_stream(fp)) {
return CMD_EXEC_FATAL_ERROR;
}
/* Write transistor pairs using the technology model */
fp << "Xpmos_" << trans_name_postfix << " ";
fp << input_port_name << " ";
fp << gate_port_name << " ";
fp << output_port_name << " ";
fp << "LVDD ";
fp << tech_lib.transistor_model_name(tech_model, TECH_LIB_TRANSISTOR_PMOS) << TRANSISTOR_WRAPPER_POSTFIX;
fp << " W=" << std::setprecision(10) << trans_width;
fp << "\n";
return CMD_EXEC_SUCCESS;
}
/********************************************************************
* Generate the SPICE modeling for the NMOS part of a pass-gate logic
*
* This function is created to be shared by pass-transistor and
* transmission-gate SPICE netlist writer
*
* Note:
* - This function does NOT create a file
* but requires a file stream created
* - This function only output SPICE modeling for
* a pass-gate. Any preprocessing or subckt definition should not be included!
*******************************************************************/
static
int print_spice_passgate_nmos_modeling(std::fstream& fp,
const std::string& trans_name_postfix,
const std::string& input_port_name,
const std::string& gate_port_name,
const std::string& output_port_name,
const TechnologyLibrary& tech_lib,
const TechnologyModelId& tech_model,
const float& trans_width) {
if (false == valid_file_stream(fp)) {
return CMD_EXEC_FATAL_ERROR;
}
fp << "Xnmos_" << trans_name_postfix << " ";
fp << input_port_name << " ";
fp << gate_port_name << " ";
fp << output_port_name << " ";
fp << "LGND ";
fp << tech_lib.transistor_model_name(tech_model, TECH_LIB_TRANSISTOR_NMOS) << TRANSISTOR_WRAPPER_POSTFIX;
fp << " W=" << std::setprecision(10) << trans_width;
fp << "\n";
return CMD_EXEC_SUCCESS;
}
/********************************************************************
* Generate the SPICE subckt for a pass-transistor
*
* Schematic
*
* sel
* |
* ===
* | |
* in -- ---out
*
*******************************************************************/
static
int print_spice_pass_transistor_subckt(std::fstream& fp,
const ModuleManager& module_manager,
const ModuleId& module_id,
const CircuitLibrary& circuit_lib,
const CircuitModelId& circuit_model,
const TechnologyLibrary& tech_lib,
const TechnologyModelId& tech_model) {
if (false == valid_file_stream(fp)) {
return CMD_EXEC_FATAL_ERROR;
}
/* Find the input and output ports:
* we do NOT support global ports here,
* it should be handled in another type of inverter subckt (power-gated)
*/
std::vector<CircuitPortId> input_ports = circuit_lib.model_ports_by_type(circuit_model, CIRCUIT_MODEL_PORT_INPUT, true);
std::vector<CircuitPortId> output_ports = circuit_lib.model_ports_by_type(circuit_model, CIRCUIT_MODEL_PORT_OUTPUT, true);
/* Make sure:
* There is only 2 input port and 1 output port,
* each size of which is 1
*/
VTR_ASSERT(2 == input_ports.size());
for (const auto& input_port : input_ports) {
VTR_ASSERT(1 == circuit_lib.port_size(input_port));
}
VTR_ASSERT( (1 == output_ports.size()) && (1 == circuit_lib.port_size(output_ports[0])) );
int status = CMD_EXEC_SUCCESS;
/* Print the inverter subckt definition */
print_spice_subckt_definition(fp, module_manager, module_id);
/* Consider use size/bin to compact layout:
* Try to size transistors to the max width for each bin
* The last bin may not reach the max width
*/
float regular_nmos_bin_width = tech_lib.transistor_model_max_width(tech_model, TECH_LIB_TRANSISTOR_NMOS);
float total_nmos_width = circuit_lib.pass_gate_logic_nmos_size(circuit_model)
* tech_lib.transistor_model_min_width(tech_model, TECH_LIB_TRANSISTOR_NMOS);
int num_nmos_bins = std::ceil(total_nmos_width / regular_nmos_bin_width);
float last_nmos_bin_width = std::fmod(total_nmos_width, regular_nmos_bin_width);
for (int ibin = 0; ibin < num_nmos_bins; ++ibin) {
float curr_bin_width = regular_nmos_bin_width;
/* For last bin, we need an irregular width */
if ((ibin == num_nmos_bins - 1)
&& (0. != last_nmos_bin_width)) {
curr_bin_width = last_nmos_bin_width;
}
status = print_spice_passgate_nmos_modeling(fp,
std::to_string(ibin),
circuit_lib.port_prefix(input_ports[0]),
circuit_lib.port_prefix(input_ports[1]),
circuit_lib.port_prefix(output_ports[0]),
tech_lib,
tech_model,
curr_bin_width);
if (CMD_EXEC_FATAL_ERROR == status) {
return status;
}
}
print_spice_subckt_end(fp, module_manager.module_name(module_id));
return status;
}
/********************************************************************
* Generate the SPICE subckt for a transmission gate
*
* Schematic
*
* selb
* |
* o
* ===
* | |
* in -- ---out
* | |
* ===
* |
* sel
*
*******************************************************************/
static
int print_spice_transmission_gate_subckt(std::fstream& fp,
const ModuleManager& module_manager,
const ModuleId& module_id,
const CircuitLibrary& circuit_lib,
const CircuitModelId& circuit_model,
const TechnologyLibrary& tech_lib,
const TechnologyModelId& tech_model) {
if (false == valid_file_stream(fp)) {
return CMD_EXEC_FATAL_ERROR;
}
/* Find the input and output ports:
* we do NOT support global ports here,
* it should be handled in another type of inverter subckt (power-gated)
*/
std::vector<CircuitPortId> input_ports = circuit_lib.model_ports_by_type(circuit_model, CIRCUIT_MODEL_PORT_INPUT, true);
std::vector<CircuitPortId> output_ports = circuit_lib.model_ports_by_type(circuit_model, CIRCUIT_MODEL_PORT_OUTPUT, true);
/* Make sure:
* There is only 3 input port and 1 output port,
* each size of which is 1
*/
VTR_ASSERT(3 == input_ports.size());
for (const auto& input_port : input_ports) {
VTR_ASSERT(1 == circuit_lib.port_size(input_port));
}
VTR_ASSERT( (1 == output_ports.size()) && (1 == circuit_lib.port_size(output_ports[0])) );
int status = CMD_EXEC_SUCCESS;
/* Print the inverter subckt definition */
print_spice_subckt_definition(fp, module_manager, module_id);
/* Consider use size/bin to compact layout:
* Try to size transistors to the max width for each bin
* The last bin may not reach the max width
*/
float regular_pmos_bin_width = tech_lib.transistor_model_max_width(tech_model, TECH_LIB_TRANSISTOR_PMOS);
float total_pmos_width = circuit_lib.pass_gate_logic_pmos_size(circuit_model)
* tech_lib.model_pn_ratio(tech_model)
* tech_lib.transistor_model_min_width(tech_model, TECH_LIB_TRANSISTOR_PMOS);
int num_pmos_bins = std::ceil(total_pmos_width / regular_pmos_bin_width);
float last_pmos_bin_width = std::fmod(total_pmos_width, regular_pmos_bin_width);
for (int ibin = 0; ibin < num_pmos_bins; ++ibin) {
float curr_bin_width = regular_pmos_bin_width;
/* For last bin, we need an irregular width */
if ((ibin == num_pmos_bins - 1)
&& (0. != last_pmos_bin_width)) {
curr_bin_width = last_pmos_bin_width;
}
status = print_spice_passgate_pmos_modeling(fp,
std::to_string(ibin),
circuit_lib.port_prefix(input_ports[0]),
circuit_lib.port_prefix(input_ports[2]),
circuit_lib.port_prefix(output_ports[0]),
tech_lib,
tech_model,
curr_bin_width);
if (CMD_EXEC_FATAL_ERROR == status) {
return status;
}
}
/* Consider use size/bin to compact layout:
* Try to size transistors to the max width for each bin
* The last bin may not reach the max width
*/
float regular_nmos_bin_width = tech_lib.transistor_model_max_width(tech_model, TECH_LIB_TRANSISTOR_NMOS);
float total_nmos_width = circuit_lib.pass_gate_logic_nmos_size(circuit_model)
* tech_lib.transistor_model_min_width(tech_model, TECH_LIB_TRANSISTOR_NMOS);
int num_nmos_bins = std::ceil(total_nmos_width / regular_nmos_bin_width);
float last_nmos_bin_width = std::fmod(total_nmos_width, regular_nmos_bin_width);
for (int ibin = 0; ibin < num_nmos_bins; ++ibin) {
float curr_bin_width = regular_nmos_bin_width;
/* For last bin, we need an irregular width */
if ((ibin == num_nmos_bins - 1)
&& (0. != last_nmos_bin_width)) {
curr_bin_width = last_nmos_bin_width;
}
status = print_spice_passgate_nmos_modeling(fp,
std::to_string(ibin),
circuit_lib.port_prefix(input_ports[0]),
circuit_lib.port_prefix(input_ports[1]),
circuit_lib.port_prefix(output_ports[0]),
tech_lib,
tech_model,
curr_bin_width);
if (CMD_EXEC_FATAL_ERROR == status) {
return status;
}
}
print_spice_subckt_end(fp, module_manager.module_name(module_id));
return status;
}
/********************************************************************
* Generate the SPICE subckt for a pass-gate
*
* Note:
* - This function supports both pass-transistor
* and transmission gates
*******************************************************************/
int print_spice_passgate_subckt(std::fstream& fp,
const ModuleManager& module_manager,
const ModuleId& module_id,
const CircuitLibrary& circuit_lib,
const CircuitModelId& circuit_model,
const TechnologyLibrary& tech_lib,
const TechnologyModelId& tech_model) {
int status = CMD_EXEC_SUCCESS;
if (CIRCUIT_MODEL_PASS_GATE_TRANSISTOR == circuit_lib.pass_gate_logic_type(circuit_model)) {
status = print_spice_pass_transistor_subckt(fp,
module_manager, module_id,
circuit_lib, circuit_model,
tech_lib, tech_model);
} else if (CIRCUIT_MODEL_PASS_GATE_TRANSMISSION == circuit_lib.is_power_gated(circuit_model)) {
status = print_spice_transmission_gate_subckt(fp,
module_manager, module_id,
circuit_lib, circuit_model,
tech_lib, tech_model);
}
return status;
}
} /* end namespace openfpga */

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@ -0,0 +1,30 @@
#ifndef SPICE_PASSGATE_H
#define SPICE_PASSGATE_H
/********************************************************************
* Include header files that are required by function declaration
*******************************************************************/
#include <string>
#include <map>
#include "module_manager.h"
#include "circuit_library.h"
#include "technology_library.h"
/********************************************************************
* Function declaration
*******************************************************************/
/* begin namespace openfpga */
namespace openfpga {
int print_spice_passgate_subckt(std::fstream& fp,
const ModuleManager& module_manager,
const ModuleId& module_id,
const CircuitLibrary& circuit_lib,
const CircuitModelId& circuit_model,
const TechnologyLibrary& tech_lib,
const TechnologyModelId& tech_model);
} /* end namespace openfpga */
#endif