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-- Copyright (C) 1996 Morgan Kaufmann Publishers, Inc
-- This file is part of VESTs (Vhdl tESTs).
-- VESTs is free software; you can redistribute it and/or modify it
-- under the terms of the GNU General Public License as published by the
-- Free Software Foundation; either version 2 of the License, or (at
-- your option) any later version.
-- VESTs is distributed in the hope that it will be useful, but WITHOUT
-- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
-- FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
-- for more details.
-- You should have received a copy of the GNU General Public License
-- along with VESTs; if not, write to the Free Software Foundation,
-- Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-- ---------------------------------------------------------------------
--
-- $Id: ch_19_source-b.vhd,v 1.2 2001-10-26 16:29:36 paw Exp $
-- $Revision: 1.2 $
--
-- ---------------------------------------------------------------------
library math;
architecture behavior of source is
begin
token_generator : process is
variable source_name : string(1 to name_max_length) := (others => ' ');
variable source_name_length : natural;
variable next_token_id : token_id_type := 0;
variable next_arrival_time : time;
variable number_of_tokens_generated : natural := 0;
variable inter_arrival_time : natural; -- in time_unit
variable sum_of_inter_arrival_times : real := 0.0; -- in time_unit
variable sum_of_squares_of_inter_arrival_times : real := 0.0; --in time_unit**2
variable random_info : random_info_record;
variable random_number : real;
use std.textio.all;
file info_file : text;
variable L : line;
use math.math_real.sqrt;
procedure write_summary is
variable measured_mean_inter_arrival_time : real
:= sum_of_inter_arrival_times / real(number_of_tokens_generated);
variable measured_std_dev_of_inter_arrival_times : real
:= sqrt ( ( sum_of_squares_of_inter_arrival_times
- sum_of_inter_arrival_times**2 / real(number_of_tokens_generated) )
/ real( number_of_tokens_generated - 1 ) );
begin
write(L, string'("Summary information for source "));
write(L, name);
write(L, string'(" up to time "));
write(L, now, unit => time_unit);
writeline(info_file, L);
write(L, string'(" Inter arrival distribution: "));
write(L, distribution_type'image(distribution));
write(L, string'(" with mean inter arrival time of "));
write(L, mean_inter_arrival_time, unit => time_unit);
writeline(info_file, L);
write(L, string'(" Number of tokens generated = "));
write(L, natural(next_token_id));
writeline(info_file, L);
write(L, string'(" Mean inter arrival time = "));
write(L, measured_mean_inter_arrival_time * time_unit, unit => time_unit);
writeline(info_file, L);
write(L, string'(" Standard deviation of inter arrival times = "));
write(L, measured_std_dev_of_inter_arrival_times * time_unit, unit => time_unit);
writeline(info_file, L);
writeline(info_file, L);
end procedure write_summary;
procedure write_trace is
begin
write(L, string'("Source "));
write(L, name);
write(L, string'(": at "));
write(L, now, unit => time_unit);
write(L, string'(" generated token "));
write(L, natural(next_token_id));
writeline(info_file, L);
end procedure write_trace;
begin
if name'length > name_max_length then
source_name := name(1 to name_max_length);
source_name_length := name_max_length;
else
source_name(1 to name'length) := name;
source_name_length := name'length;
end if;
file_open(info_file, info_file_name, write_mode);
case distribution is
when fixed =>
init_fixed(random_info, real(mean_inter_arrival_time / time_unit));
when uniform =>
init_uniform( random_info,
lower_bound => 0.0,
upper_bound => 2.0 * real(mean_inter_arrival_time / time_unit),
seed => seed );
when exponential =>
init_exponential( random_info,
mean => real(mean_inter_arrival_time / time_unit),
seed => seed );
end case;
loop
generate_random(random_info, random_number);
inter_arrival_time := natural(random_number);
next_arrival_time := inter_arrival_time * time_unit + now;
loop
wait on info_detail'transaction for next_arrival_time - now;
if info_detail'active and info_detail = summary then
write_summary;
end if;
exit when next_arrival_time = now;
end loop;
out_arc <= arc_type'( transaction => not out_arc.transaction'driving_value,
token => token_type'( source_name => source_name,
source_name_length => source_name_length,
id => next_token_id,
creation_time => now ) );
number_of_tokens_generated := number_of_tokens_generated + 1;
sum_of_inter_arrival_times := sum_of_inter_arrival_times
+ real(inter_arrival_time);
sum_of_squares_of_inter_arrival_times := sum_of_squares_of_inter_arrival_times
+ real(inter_arrival_time) ** 2;
if info_detail = trace then
write_trace;
end if;
next_token_id := next_token_id + 1;
end loop;
end process token_generator;
end architecture behavior;
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