Settings.pm

#-------------------------------------------------------------------------------
#  University of Applied Sciences Technikum Wien
#
#  Department of Embedded Systems
#  http://embsys.technikum-wien.at
#
#  Josef Ressel Center for Verification of Embedded Computing Systems
#  http://vecs.technikum-wien.at
#
#-------------------------------------------------------------------------------
#  File:              Settings.pm
#  Created on:        16.02.2015
#  $LastChangedBy$
#  $LastChangedDate$
#
#  Description:
#
# Contains helper functions to deal with FIJI Settings files.
#-------------------------------------------------------------------------------


## @file

## @class FIJI::Settings
#
# Contains helper functions to deal with FIJI Settings files.
package FIJI::Settings;

use strict;
use warnings;

use Scalar::Util 'blessed';
use Log::Log4perl qw(get_logger);
use Scalar::Util "looks_like_number";
use Config::Simple;
use Data::Dumper;
use POSIX qw(ceil);
use List::Util qw(max);

use FIJI qw(:all);

my @base_resources;

## @function new ($phase, $fiji_ini_file, $existing_settings)
# Create a new settings instance.
#
# \param $phase Tool flow phase the settings need to be compatible with.
# \param $fiji_ini_file (optional) Path to the configuration file to read.
# \param $existing_settings (optional) A reference to reuse and return
#        with values read from file. Any contained data will be cleared.
# \returns The new settings instance or a string describing the reason
#          why it could not be created.
sub new ($;$$) {
  my $logger = get_logger();
  my ($class, $phase, $fiji_ini_file, $existing_settings) = @_;

  my $fiji_settings_ref;
  # if there is no existing settings instance yet, create one
  if (!defined($existing_settings)) {
    $fiji_settings_ref = {};
    $fiji_settings_ref = bless($fiji_settings_ref, $class);
  } else {
    $fiji_settings_ref = $existing_settings;
  }
  if (!blessed($fiji_settings_ref) || !$fiji_settings_ref->isa("FIJI::Settings")) {
    my $msg;
    if (!defined($existing_settings)) {
      $msg = "Could not create FIJI::Settings instance.";
    } else {
      $msg = "Given settings are not of type FIJI::Settings.";
    }
    $logger->error($msg);
    return $msg;
  }

  # If there is a file given, try to read it. Else just create a default instance.
  if (defined($fiji_ini_file)) {
    $fiji_settings_ref = read_settingsfile($phase, $fiji_ini_file, $fiji_settings_ref);
    if (!ref($fiji_settings_ref)) {
      return $fiji_settings_ref; # actually an error message
    }
  } else {
    $fiji_settings_ref->{'design'} = {};
    _set_defaults(DESIGNMAP, $fiji_settings_ref->{'design'}, $phase);
    $fiji_settings_ref->{'fius'} = [];
  }

  @base_resources = _est_resources(DESIGNMAP->{'FREQUENCY'}->{'default'},
                                    DESIGNMAP->{'BAUDRATE'}->{'default'},
                                    DESIGNMAP->{'TIMER_WIDTH'}->{'default'},
                                    DESIGNMAP->{'RESET_DUT_IN_DURATION'}->{'default'},
                                    DESIGNMAP->{'LFSR_WIDTH'}->{'default'},0,"logarithmic");

  return $fiji_settings_ref;
}


sub _export_value {
  my $logger = get_logger();
  my ($map_ref, $k, $v_ref) = @_;

  if (defined($map_ref->{$k}->{'type'})) {
    my $orig = ${$v_ref};
    if ($map_ref->{$k}->{'type'} eq 'hexadecimal') {
      ${$v_ref} = sprintf("0x%x", $orig);
    # } elsif ($map_ref->{$k}->{'type'} eq 'natural') {
    # } elsif ($map_ref->{$k}->{'type'} eq 'boolean') {
      $logger->trace("Converted value of $k (\"$orig\") to \"${$v_ref}\".") if ($orig ne ${$v_ref});
    }
  # } elsif (defined($map_ref->{$k}->{'values'})) {
  }
}

## @method save ($fiji_ini_file)
# @brief Store contained FIJI Settings to file.
#
# @ATTENTION Will happily overwrite existing files!
#
# \param fiji_ini_file The file name to write the FIJI Settings to.
sub save ($) {
  my $logger = get_logger();
  my ($self, $fiji_ini_file) = @_;
  return "No file name given" if !defined($fiji_ini_file);

  my $fiji_ini = new Config::Simple(syntax=>'ini');
  my $design_ref;
  my $fiu_cnt = 0;
  foreach my $key (keys %{$self}) {
    my $val = $self->{$key};
    if (ref(\$val) eq "REF") {
      if (ref($val) eq "HASH") {
        if ($key eq "design") {
          $design_ref = $val;
          next;
        }
      } elsif (ref($val) eq "ARRAY") {
        if ($key eq "fius") {
          foreach my $fiu (@{$val}) {
            my $ini_fiu;
            
            foreach my $k (keys(%{$fiu})) {
              my $ini_name = FIUMAP->{$k}->{'ini_name'};
              if (!defined($fiu->{$k})) {
                $logger->debug("Skip saving undefined value of FIU constant with key $ini_name.");
                next;
              }
              # Copy value to new hash with external naming.
              $ini_fiu->{$ini_name} = $fiu->{$k};
              # Convert value to external representation
              _export_value(FIUMAP, $k, \$ini_fiu->{$ini_name});
              $logger->trace(sprintf("Exporting FIU%d setting %s -> %s (%s -> %s).",
                                     $fiu_cnt,
                                     $k,
                                     $ini_name,
                                     defined($fiu->{$k}) ? $fiu->{$k} : "undef",
                                     defined($ini_fiu->{$ini_name}) ? $ini_fiu->{$ini_name} : "undef"),
                            );
            }
            $fiji_ini->set_block("FIU" . $fiu_cnt++, $ini_fiu);
          }
          next;
        }
      }
    }
    my $err = "Unknown element found in FIJI Settings: \"$val\"";
    $logger->error($err);
    return $err;
  }
  $design_ref->{'FIU_NUM'} = $fiu_cnt;
  my $ini_design;
  foreach my $k (keys(%{$design_ref})) {
    my $ini_name = DESIGNMAP->{$k}->{'ini_name'};
    if (!defined($design_ref->{$k})) {
      $logger->debug("Skip saving undefined value of design constant with key $ini_name.");
      next;
    }
    # Copy value to new hash with external naming.
    $ini_design->{$ini_name} = $design_ref->{$k};
    # Convert value to external representation
    _export_value(DESIGNMAP, $k, \$ini_design->{$ini_name});
    $logger->trace(sprintf("Exporting Design setting %s -> %s (%s -> %s).",
                           $k,
                           $ini_name,
                           defined($design_ref->{$k}) ? $design_ref->{$k} : "undef",
                           defined($ini_design->{$ini_name}) ? $ini_design->{$ini_name} : "undef"),
                  );
  }
  $fiji_ini->set_block("CONSTS", $ini_design);

  if (!defined($fiji_ini->write($fiji_ini_file))) {
    my $err = Config::Simple->error();
    $logger->error($err);
    return $err;
  }
  return undef;
}


## @function read_settingsfile ($phase, $fiji_ini_file)
# @brief Load the FIJI Settings file containing design and FIU constants.
#
# \param phase  Tool flow phase the settings stored in the given file
#               need to be compatible with.
# \param fiji_ini_file The name of an .ini file with FIJI Settings:
#         - a 'consts' block containing the constants specified by
#           \ref _sanitize_design.
#         - at least one FIU block named "FIU<number>" where "<number>"
#           is a strictly increasing integer starting with 0 containing
#           the constants for the respective FIU, see \ref _sanitize_fiu
#
# \returns a reference to the hash containing the read constants.
sub read_settingsfile ($$$) {
  my $logger = get_logger();
  my ($phase, $fiji_ini_file, $existing_settings) = @_;
  my $fiji_ini;
  eval { $fiji_ini = new Config::Simple($fiji_ini_file) }; # pesky library tries to die on syntax errors
  if (!defined($fiji_ini)) {
    my $submsg = defined($@) ? $@ : Config::Simple->error();
    if (length($submsg) == 0) {
      $submsg = "Empty file?";
    }
    my $msg = "Could not read config file \"$fiji_ini_file\": $submsg";
    $logger->error($msg);
    return $msg;
  }

  my $design_ref = $fiji_ini->get_block("CONSTS");
  if (!(%$design_ref)) {
    my $msg = "Could not fetch CONSTS block from config file \"$fiji_ini_file\"";
    $logger->error($msg);
    return $msg;
  }
  _set_defaults(DESIGNMAP, $design_ref, $phase);

  $design_ref = _rename_import(DESIGNMAP, $design_ref);
  if (!defined($design_ref)) {
    my $msg = "Design constants do not match the FIJI Settings naming scheme.";
    $logger->error($msg);
    return $msg;
  }

  # Create a new instance or reuse the shallow hull of the existing one
  my $fiji_settings_ref;
  if (!defined($existing_settings)) {
    $fiji_settings_ref = {};
    bless($fiji_settings_ref, "FIJI::Settings");
  } else {
    $fiji_settings_ref = $existing_settings;
    # Clear the hash
    for (keys %$fiji_settings_ref) {
        delete $fiji_settings_ref->{$_};
    }
   }
  if (!blessed($fiji_settings_ref) || !$fiji_settings_ref->isa("FIJI::Settings")) {
    my $msg;
    if (!defined($existing_settings)) {
      $msg = "Could not create FIJI::Settings instance.";
    } else {
      $msg = "Given settings are not of type FIJI::Settings.";
    }
    $logger->error($msg);
    return $msg;
  }
  $fiji_settings_ref->{'design'} = $design_ref;
  $fiji_settings_ref->{'fius'} = [];

  # sanitize and validate read design constants
  $design_ref = _sanitize_design($design_ref, $phase);
  if (!ref($design_ref)) {
    $logger->error($design_ref);
    return $design_ref;
  }

  my $fiu_num = 0;
  # loop over all read fius
  while (1) {
    my $fiu_name = "FIU" . $fiu_num;
    my $fiu_ref = $fiji_ini->get_block($fiu_name);
    if (!(%$fiu_ref)) {
      last;
    }
    $fiu_ref = _rename_import(FIUMAP, $fiu_ref);
    if (!defined($design_ref)) {
      my $msg = "FIU constants of $fiu_name do not match the FIJI Settings naming scheme.";
      $logger->error($msg);
      return $msg;
    }

    my $tmp_fiu = {};
    _set_defaults(FIUMAP, $tmp_fiu, $phase);
    # overwrite default entries
    foreach my $k (keys(%{$fiu_ref})) {
      $tmp_fiu->{$k} = $fiu_ref->{$k};
    }
    $fiu_ref = $tmp_fiu;

    $fiu_ref = _sanitize_fiu($fiu_ref, $phase);
    if (!ref($fiu_ref)) {
      my $msg = "(Some) constants for $fiu_name in FIJI Settings are invalid.";
      $logger->error($msg);
      return $msg;
    }
    $fiji_settings_ref->{'fius'}->[$fiu_num] = $fiu_ref;
    $fiu_num++;
    $logger->trace("Read in $fiu_name from FIJI Settings file successfully.");
  }

  if ($fiu_num == 0) {
    $logger->debug("Could not fetch any FIU blocks from config file \"$fiji_ini_file\"");
  }

  # FIU_NUM is optional in the Settings file... if it was set check that
  # it corresponds to the number of FIU<number> blocks.
  if (defined($design_ref->{'FIU_NUM'}) && $design_ref->{'FIU_NUM'} != $fiu_num) {
      my $msg = FIU_NUM->{'ini_name'} . " does not match the numbers of FIU blocks found.";
      $logger->error($msg);
      return $msg;
  } else {
    $design_ref->{'FIU_NUM'} = $fiu_num; # assume the best if FIU_NUM constant is not given
  }

  splice(@{$fiji_settings_ref->{'fius'}}, $fiu_num);
  $logger->info("Successfully read in design constants and $fiu_num FIU definitions from FIJI Settings file \"$fiji_ini_file\".");
  return $fiji_settings_ref;
}

## @method set_fiu_defaults (%$fiu_ref)
# @brief Overwrite existing fields (if defined) with defaults defined in FIJI.pm.
#
sub set_fiu_defaults ($) {
  my ($self, $consts_ref) = @_;
  return _set_defaults(FIUMAP, $consts_ref);
}

## @function _set_defaults (%$map_ref, %$consts_ref)
# @brief Set defaults according to FIJI.pm.
sub _set_defaults {
  my $logger = get_logger();
  my ($map_ref, $consts_ref, $phase) = @_;
  foreach my $k (keys(%{$map_ref})) {
    if (exists($map_ref->{$k}->{'default'})) {
      # Set default only if it is not mandatory in the given phase.
      if (defined($phase) && scalar(grep {$_ eq $phase} @{$map_ref->{$k}->{'phases_opt'}}) == 0) {
        next;
      }

      # Also, do not overwrite existing values
      if (defined($consts_ref->{$k})) {
        next;
      }
      $consts_ref->{$k} = $map_ref->{$k}->{default};
      $logger->trace(sprintf("Adding default constant: %s (%s) = %s.", $k, $map_ref->{$k}->{'ini_name'}, $map_ref->{$k}->{default}));
    }
  }
}


sub validate_design_value {
  my ($k, $v_ref) = @_;
  return validate_value(DESIGNMAP, $k, $v_ref);
}

sub validate_fiu_value {
  my ($k, $v_ref) = @_;
  return validate_value(FIUMAP, $k, $v_ref);
}

## @function validate_value (%$map_ref, $k, $$v_ref, $old, $log_func)
#   Do validation (and conversation from external->internal representation)
#
#   \param map_ref  reference to FIJI Settings mappings
#   \param k        key identifying the respective setting
#   \param v_ref    scalar reference to the proposed value (that may be modified)
#   \param old      (optional) previously valid value
#   \param log_func (optional) the (log4perl) log function to use
#                   (defaul is \&Log::Log4perl::Logger::trace)
sub validate_value ($$$;$$) {
  my $logger = get_logger();
  my ($map_ref, $k, $v_ref, $old, $log_func) = @_;
  $log_func = \&Log::Log4perl::Logger::trace if !defined($log_func);
  if (defined($map_ref->{$k}->{'type'})) {
    my $orig = ${$v_ref};
    # FIXME: check if the constant is depending on another constant, that needs to be enabled.
    # my $dependency = @{$map_ref->{$k}->{'depends_on'}};
    # if (defined($dependency) && defined(@{$map_ref->{$dependency}->{'value'}}
    # }

    if ($map_ref->{$k}->{'type'} eq 'net') {
      # TODO: check syntax? there is nothing more to do in here unless we supply allowed nets...
      # which is actually possible because the input netlist is stored in the settings as well
    } elsif ($map_ref->{$k}->{'type'} eq 'hexadecimal') {
      if ($orig !~ /^(0|(0[xX][[:xdigit:]]+))$/) {
        $log_func->($logger, "$k: $orig does not look like a natural hexadecimal number.");
        return 0;
      }
      ${$v_ref} = hex($orig);
      # Check for natural value range. Should never trigger due to the regex above.
      if (${$v_ref} < 0) {
        $log_func->($logger, "$k: $orig is negative.");
        return 0;
      }
    } elsif ($map_ref->{$k}->{'type'} eq 'natural') {
      # Match hexadecimal, binary, octal and decimal numbers (the latter also in scientific notation)
      if ($orig !~ /^(0|(0(x[0-9a-fA-F]+|[0-7]+))|(0b[01]+)|([1-9][0-9]*(e(-[0-9])?[0-9]+)?))$/) {
        $log_func->($logger, "$k: $orig does not look like a number.");
        return 0;
      }
      
      # convert non-decimal (hexadecimal, binary, octal) values to decimal
      ${$v_ref} = oct($orig) if $orig =~ /^0/;
      if (!looks_like_number(${$v_ref})) {
        $log_func->($logger, "$k: $orig does not look like a number.");
        return 0;
      }
      # Check for natural value range. Should never trigger due to the regex above.
      if (${$v_ref} < 0) {
        $log_func->($logger, "$k: $orig is negative.");
        return 0;
      }
    } elsif ($map_ref->{$k}->{'type'} eq 'boolean') {
      # convert strings to binary if need be
      if (!defined($orig)) {
        $log_func->($logger, "$k: \"undef\" is not a boolean value.");
        return 0;
      } elsif (lc($orig) eq 'true') {
        $orig = 1;
      } elsif (lc($orig) eq 'false') {
        $orig = 0;
      }
      if (($orig ne '0') && ($orig ne '1')) {
        $log_func->($logger, "$k: \"$orig\" does not look like a boolean value.");
        return 0;
      }
      # ensure proper boolean value, i.e. 0 or 1
      ${$v_ref} = (!!$orig) ? 1 : 0;
    }
    $logger->trace("Converted value of $k (\"$orig\") to \"${$v_ref}\".") if (defined($orig) && $orig ne ${$v_ref});
  }

  if (defined($map_ref->{$k}->{'values'})) {
    my $values_ref = $map_ref->{$k}->{'values'};
    if (ref($values_ref) eq 'ARRAY') {
      # Look for given value in allowed values
      if (scalar(grep {$_ eq ${$v_ref}} @{$values_ref}) == 0) {
        $log_func->($logger, "$k: ${$v_ref} is not allowed. Allowed values are: " . join(", ", @{$map_ref->{$k}->{'values'}}));
        return 0;
      }
    } elsif (ref($values_ref) eq 'CODE') {
      if (!$values_ref->(${$v_ref}, $old)) {
        $log_func->($logger, "$k: ${$v_ref} is not allowed.");
        return 0;
      }
    }
  }
  return 1;
}


# @function _rename_import (%$map_ref, %$consts_ref)
# Rename and convert entries in consts_ref according to map_ref.
#
# This function takes a hash of FIJI Settings and converts its contents
# to the respective internal representation. This allows to use different
# names and value representations in the external file than within the
# implementation.
#
# \returns $consts_ref, or undef on errors
sub _rename_import {
  my $logger = get_logger();
  my ($map_ref, $consts_ref) = @_;
  if (ref($consts_ref) ne 'HASH') {
    $logger->error("Parameter is not a reference to a hash (containing design constants).");
    return undef;
  }

  # Iterating over respective hash from FIJI.pm and rename the entries
  # to match our internal naming scheme.
  foreach my $k (keys(%{$map_ref})) {
    my $ini_name = $map_ref->{$k}->{'ini_name'};
    if (exists($consts_ref->{$ini_name}) && $ini_name ne $k) {
      $consts_ref->{$k} = $consts_ref->{$ini_name};
      $logger->trace(sprintf("Renaming Design setting %s -> %s (=%s).",
                             $ini_name,
                             $k,
                             defined($consts_ref->{$ini_name}) ? $consts_ref->{$ini_name} : "undef"),
                    );
      delete $consts_ref->{$ini_name};
    }
  }
  foreach my $entry_key (keys(%{$consts_ref})) {
    if (!exists($map_ref->{$entry_key})) {
      $logger->debug("Deleting unknown setting %s = %s.", $entry_key, $consts_ref->{$entry_key});
      delete $consts_ref->{$entry_key};
    }
  }

  return $consts_ref;
}


## @function _sanitize_fiu (%$fiu_ref, $phase)
# @brief Convert and sanity check FIJI Settings.
#
# \param fiu_ref a reference to a hash containing FIJI Settings for a
#                single FIU.
#
# \returns A new hash with all constants required in the FIU settings
#          in sanitized form, or undef on errors.
sub _sanitize_fiu ($;$) {
  my $logger = get_logger();
  my ($fiu_ref, $phase) = @_;
  if (ref($fiu_ref) ne 'HASH') {
    my $msg = "Parameter is not a reference to a hash (containing FIU constants).";
    $logger->error($msg);
    return $msg;
  }

  $fiu_ref = _validate_hashmap(FIUMAP, $fiu_ref, $phase);
  if (!ref($fiu_ref)) {
      $logger->error("Could not validate Design Constants.");
      return $fiu_ref;
  }

  return $fiu_ref;
}


sub _disabled_via_dependency ($$$) {
  my ($map_ref, $consts_ref, $k) = @_;
  my $dependency = $map_ref->{$k}->{'depends_on'};
  return defined($dependency) && !$consts_ref->{$dependency};
}


sub _validate_hashmap ($$;$) {
  my $logger = get_logger();
  my ($map_ref, $consts_ref, $phase) = @_;
  my @map_keys = keys(%{$map_ref});
  foreach my $entry_key (keys(%{$consts_ref})) {
    my $forbidden_by = $map_ref->{$entry_key}->{'forbidden_by'};
    my $ini_name = $map_ref->{$entry_key}->{'ini_name'};
    
    if (!exists($map_ref->{$entry_key})) {
      $logger->debug("Deleting unknown setting %s = %s.", $entry_key, $consts_ref->{$entry_key});
      next;
    }

    @map_keys = grep {$_ ne $entry_key} @map_keys; # mark constant key as done
    if (_disabled_via_dependency($map_ref, $consts_ref, $entry_key)) {
      $logger->debug(sprintf("Key %s is disabled via %s. Skipping validation.", $entry_key, $map_ref->{$entry_key}->{'depends_on'}));
    } elsif (!validate_value($map_ref, $entry_key, \$consts_ref->{$entry_key})) {
      my $msg = sprintf("%s = %s is invalid.", $entry_key, !defined($consts_ref->{$entry_key}) ? "<undef>" : $consts_ref->{$entry_key});
      $logger->error($msg);
      return $msg;
    }

    if ( defined ($forbidden_by) && $consts_ref->{$entry_key} &&  $consts_ref->{$forbidden_by} ) {
      my $msg = "$entry_key is forbidden when $forbidden_by is enabled";
      $logger->error($msg);
      return $msg;
    }
  }

  if (!defined($phase)) {
    # If there is no phase we are creating an "empty" hash that has
    # all possible defaults set earlier already and the there is
    # nothing we can or should do here.
    return $consts_ref;
  }

  # Iterate over the constants defined in FIJI.pm that apparently are
  # not contained in $consts_ref.
  foreach my $k (@map_keys) {
    my $dependency   = $map_ref->{$k}->{'depends_on'};
    if (
        scalar(grep {$_ eq $phase} @{$map_ref->{$k}->{'phases_opt'}}) == 0 && # mandatory in current phase
        !_disabled_via_dependency($map_ref, $consts_ref, $k) # no dependency or dependency is enabled
       ) {
      my $msg = "$k is mandatory in phase $phase.";
      $logger->error($msg);
      return $msg;
    }

  }

  # TODO: implement the same mechanism with forbidden_by

  return $consts_ref
}


## @function _sanitize_design (%$consts_ref, $phase)
# @brief Sanity check FIJI Design Settings.
#
# The function deals with sanity checks for the values
# themselves. It checks for the following conditions:
#
#   - FIU_NUM: > 0
#   - FIU_CFG_BITS: > 0
#   - TIMER_WIDTH: > 0, <= 16
#   - ID: > 0, < 2^15-1
#   - BAUDRATE: > 0
#
# \param consts_ref a reference to a hash containing some design settings
# \param phase the tool flow phase that defines the rules to check against
#
# \returns The given hash with all constants required in the design
#          settings in sanitized form, or an error message.
sub _sanitize_design {
  my $logger = get_logger();
  my ($consts_ref, $phase) = @_;
  if (ref($consts_ref) ne 'HASH') {
    my $msg = "Parameter is not a reference to a hash (containing design constants).";
    $logger->error($msg);
    return $msg;
  }
  
  # check for sane values
  $consts_ref = _validate_hashmap(DESIGNMAP, $consts_ref, $phase);
  if (!ref($consts_ref)) {
      my $msg = "Could not validate Design Constants.";
      $logger->error($msg);
      return "$msg $consts_ref";
  }

  if (($consts_ref->{'FIU_CFG_BITS'} <= 0)) {
      my $msg = "FIU_CFG_BITS is <= 0.";
      $logger->error($msg);
      return $msg;
  }
  if (($consts_ref->{'TIMER_WIDTH'} <= 0) || ($consts_ref->{'TIMER_WIDTH'} > 16)) {
      my $msg = "TIMER_WIDTH is invalid ($consts_ref->{'TIMER_WIDTH'}).";
      $logger->error($msg);
      return $msg;
  }
  if (defined($consts_ref->{'ID'}) && ($consts_ref->{ID} < 0 || $consts_ref->{ID} > (2**16 - 1))) {
      my $msg = "ID is invalid ($consts_ref->{ID}).";
      $logger->error($msg);
      return $msg;
  }
  if (($consts_ref->{'BAUDRATE'} <= 0)) {
      my $msg = "BAUDRATE missing is <= 0.";
      $logger->error($msg);
      return $msg;
  }

  return $consts_ref;
}

sub _log2 {
    my $val = shift;
    return ($val > 0) ? (log($val)/log(2)) : 0;
}

## Determined by experiment & fitted by scipy.optimize.curve_fit
#
sub _est_resources {
    my $logger = get_logger();
    my ($FREQUENCY, $BAUD, $TIMER_WIDTH, $RESET_CYCLES, $LFSR_WIDTH, $FIU_NUM, $algo) = @_;

    # FIXME where do we put these values? they are likely to change if the VHDL
    # source is changed...

    $algo = "logarithmic" if (!defined $algo);

    my $registers;
    my $lutsum;
    my $lut6;
    my $comb;

    $logger->debug("FREQUENCY $FREQUENCY out of range (1000000 - 500000000)")  if ($FREQUENCY    < 1000000 || $FREQUENCY    > 500000000);
    $logger->debug("BAUD $BAUD out of range (9600 - 3000000)")                 if ($BAUD         < 9600    || $BAUD         > 3000000);
    $logger->debug("TIMER_WIDTH $TIMER_WIDTH out of range (1 - 8)")            if ($TIMER_WIDTH  < 1       || $TIMER_WIDTH  > 8);
    $logger->debug("RESET_CYCLES $RESET_CYCLES out of range (1 - 16)")         if ($RESET_CYCLES < 1       || $RESET_CYCLES > 16);
    $logger->debug("LFSR_WIDTH $LFSR_WIDTH out of range (16 - 64)")            if ($LFSR_WIDTH   < 16      || $LFSR_WIDTH   > 64);
    $logger->debug("FIU_NUM $FIU_NUM out of range (0 - 64)")                   if ($FIU_NUM      < 1       || $FIU_NUM      > 64);

    if ($algo eq "logarithmic") {
        $registers  = 105.90215234;
        $registers += (-8.78501935753e-10) * ($FREQUENCY)    + (2.02400278472)   * (_log2($FREQUENCY));
        $registers += (-1.92362445319e-08) * ($BAUD)         + (-1.99903895447)  * (_log2($BAUD));
        $registers += (25.294652022)       * ($TIMER_WIDTH)  + (-3.6942823707)   * (_log2($TIMER_WIDTH));
        $registers += (-0.0388887762348)   * ($RESET_CYCLES) + (1.12647034117)   * (_log2($RESET_CYCLES));
        $registers += (1.0012871074)       * ($LFSR_WIDTH)   + (-0.035302419887) * (_log2($LFSR_WIDTH));
        $registers += (13.0019033469)      * ($FIU_NUM)      + (-1.06808285072)  * (_log2($FIU_NUM));

        $lutsum  = 141.184641269;
        $lutsum += (5.14383788335e-09) * ($FREQUENCY)    + (4.44319121639)   * (_log2($FREQUENCY));
        $lutsum += (8.15160754702e-07) * ($BAUD)         + (-4.96956691254)  * (_log2($BAUD));
        $lutsum += (21.280632646)      * ($TIMER_WIDTH)  + (-7.40399315196)  * (_log2($TIMER_WIDTH));
        $lutsum += (0.0181923149046)   * ($RESET_CYCLES) + (1.33545547133)   * (_log2($RESET_CYCLES));
        $lutsum += (0.0264092868862)   * ($LFSR_WIDTH)   + (-0.817645982805) * (_log2($LFSR_WIDTH));
        $lutsum += (3.88874581602)     * ($FIU_NUM)      + (0.262418360097)  * (_log2($FIU_NUM));

    #    $lut6  = 108.374524207;
    #    $lut6 += (2.01487096337e-09)*($FREQUENCY) + (1.83543879998)*(_log2($FREQUENCY));
    #    $lut6 += (-3.30317499662e-07)*($BAUD) + (-2.11380910663)*(_log2($BAUD));
    #    $lut6 += (11.2173091132)*($TIMER_WIDTH) + (-4.43369929787)*(_log2($TIMER_WIDTH));
    #    $lut6 += (-0.154956213792)*($RESET_CYCLES) + (1.35245013922)*(_log2($RESET_CYCLES));
    #    $lut6 += (0.0215685459865)*($LFSR_WIDTH) + (-0.668625639476)*(_log2($LFSR_WIDTH));
    #    $lut6 += (2.42277105024)*($FIU_NUM) + (0.194734794118)*(_log2($FIU_NUM));

    #    $comb  = 137.316369361;
    #    $comb += (1.6814589881e-08)*($FREQUENCY) + (8.4678903776)*(_log2($FREQUENCY));
    #    $comb += (3.49377938517e-06)*($BAUD) + (-9.93771915344)*(_log2($BAUD));
    #    $comb += (41.3625159451)*($TIMER_WIDTH) + (-12.9768582431)*(_log2($TIMER_WIDTH));
    #    $comb += (0.287036354808)*($RESET_CYCLES) + (0.866505995634)*(_log2($RESET_CYCLES));
    #    $comb += (0.0360914264988)*($LFSR_WIDTH) + (-1.11962532017)*(_log2($LFSR_WIDTH));
    #    $comb += (3.88031724863)*($FIU_NUM) + (0.443465557591)*(_log2($FIU_NUM));
    } elsif ($algo eq "polynomial") {

        $registers = -2010875.59555;
        $registers += (2.76229402251e-07)*($FREQUENCY) + (-1.99515157117e-15)*($FREQUENCY**2) + (3.00590523596e-24)*($FREQUENCY**3);
        $registers += (-4.12206137854)*($BAUD) + (3.43014697591e-05)*($BAUD**2) + (-1.09771659281e-11)*($BAUD**3);
        $registers += (19.1505478618)*($TIMER_WIDTH) + (0.968580877998)*($TIMER_WIDTH**2) + (-0.0572727376031)*($TIMER_WIDTH**3);
        $registers += (2639374.42117)*($RESET_CYCLES) + (-659843.417883)*($RESET_CYCLES**2) + (31421.1133492)*($RESET_CYCLES**3);
        $registers += (3990.13449895)*($LFSR_WIDTH) + (-124.660493304)*($LFSR_WIDTH**2) + (1.11304032394)*($LFSR_WIDTH**3);
        $registers += (11.9791223372)*($FIU_NUM) + (0.0532451990358)*($FIU_NUM**2) + (-0.000610665213464)*($FIU_NUM**3);

        $lutsum = 94081.448429;
        $lutsum += (6.84901011695e-07)*($FREQUENCY) + (-5.31630997207e-15)*($FREQUENCY**2) + (8.18999405393e-24)*($FREQUENCY**3);
        $lutsum += (2.76529833194)*($BAUD) + (-2.30130317053e-05)*($BAUD**2) + (7.36465871249e-12)*($BAUD**3);
        $lutsum += (-1.31145039083)*($TIMER_WIDTH) + (4.78626536988)*($TIMER_WIDTH**2) + (-0.330321432416)*($TIMER_WIDTH**3);
        $lutsum += (-122105.518664)*($RESET_CYCLES) + (30526.6179134)*($RESET_CYCLES**2) + (-1453.65059187)*($RESET_CYCLES**3);
        $lutsum += (-2766.64987134)*($LFSR_WIDTH) + (86.4567706424)*($LFSR_WIDTH**2) + (-0.771930699286)*($LFSR_WIDTH**3);
        $lutsum += (3.54441195947)*($FIU_NUM) + (0.031558519242)*($FIU_NUM**2) + (-0.000405853019244)*($FIU_NUM**3);

    #    $lut6 = 3682107.46593
    #    $lut6 += (3.39444096763e-07)*($FREQUENCY) + (-2.85399782298e-15)*($FREQUENCY**2) + (4.47796044682e-24)*($FREQUENCY**3);
    #    $lut6 += (-5.44327330276)*($BAUD) + (4.52960038538e-05)*($BAUD**2) + (-1.44956417381e-11)*($BAUD**3);
    #    $lut6 += (-13.5605250998)*($TIMER_WIDTH) + (5.73916956842)*($TIMER_WIDTH**2) + (-0.403826909123)*($TIMER_WIDTH**3);
    #    $lut6 += (2875771582.21)*($RESET_CYCLES) + (-718942895.354)*($RESET_CYCLES**2) + (34235375.9671)*($RESET_CYCLES**3);
    #    $lut6 += (-240045086.949)*($LFSR_WIDTH) + (7501408.9663)*($LFSR_WIDTH**2) + (-66976.8657666)*($LFSR_WIDTH**3);
    #    $lut6 += (2.41751820708)*($FIU_NUM) + (0.00465166689604)*($FIU_NUM**2) + (-6.74436958278e-05)*($FIU_NUM**3);

    #    $comb = 96899684.7121
    #    $comb += (1.3719568736e-06)*($FREQUENCY) + (-1.08779793899e-14)*($FREQUENCY**2) + (1.68660125067e-23)*($FREQUENCY**3);
    #    $comb += (-130.621939943)*($BAUD) + (0.00108697725211)*($BAUD**2) + (-3.47854948947e-10)*($BAUD**3);
    #    $comb += (14.5954045564)*($TIMER_WIDTH) + (4.76821272642)*($TIMER_WIDTH**2) + (-0.30108920038)*($TIMER_WIDTH**3);
    #    $comb += (-163775236.728)*($RESET_CYCLES) + (40943809.4054)*($RESET_CYCLES**2) + (-1949705.21116)*($RESET_CYCLES**3);
    #    $comb += (3175785.67136)*($LFSR_WIDTH) + (-99243.3036534)*($LFSR_WIDTH**2) + (886.100931985)*($LFSR_WIDTH**3);
    #    $comb += (3.45401115376)*($FIU_NUM) + (0.04166391798)*($FIU_NUM**2) + (-0.000540550065177)*($FIU_NUM**3);

    }

    return ($registers, $lutsum, $lut6, $comb);
}

sub estimate_resources {
    my $logger = get_logger();
    my ($settings_ref) = @_;
    my $consts_ref = $settings_ref->{'design'};
    my $fiu_ref    = $settings_ref->{'fius'};
    my $fiu_num = @{$fiu_ref};

    my @calcrv = _est_resources($consts_ref->{'FREQUENCY'},
                                $consts_ref->{'BAUDRATE'},
                                $consts_ref->{'TIMER_WIDTH'},
                                $consts_ref->{'RESET_DUT_IN_DURATION'},
                                $consts_ref->{'LFSR_WIDTH'},
                                $fiu_num,    "logarithmic");

    my $rv = {
                regs     => sprintf("%.2f", $calcrv[0]/$base_resources[0]),
                lut_calc => sprintf("%.2f", $calcrv[1]/$base_resources[1]),
             };

    $logger->debug("ESTIMATE: current config will need Base*$rv->{'regs'} registers and Base*$rv->{'lut_calc'} combinational resources");
    return $rv;
}

1;