#!/usr/bin/perl
# 
# A perl script for automatic generation of asynchronous stimuli
# for USART input in GPSIM
# Written by Wojciech M. Zabolotny (wzab@ise.pw.edu.pl) 3 Aug 2001
# This code is so simple that I release it to public domain
# 
# Calling syntax:
# usartst [-f 1] -r divisor -o output_file -n stimuli_name times_and_strings_list
#
use strict;
use Getopt::Std;
use vars qw/$i $sim_time $bit_time $opt_f $opt_r $opt_o $opt_n *OUTFILE/;
# The global variables
$sim_time=0;
$bit_time=10;
#The procedure below sends the string of characters
sub emit_string
  {
    my $i;
    for ( $i=0 ; $i<length($_[0]) ; $i++)
      {
	emit_char(substr($_[0],$i,1));
      }
  }

#The procedure below sends the single character
sub emit_char
  {
    my $code=ord $_[0];
    my $i=1;
    emit_bit(0); #The start bit
    while ( $i<256 )
      {
	emit_bit ( $code & $i ? 1 : 0);
	$i *= 2;
      }
    emit_bit(1); #The stop bit
  }

#The procedure below sends the single bit
sub emit_bit
  {
    print OUTFILE $sim_time .  " " . $_[0] . "\n";
    $sim_time += $bit_time;
  }

getopt("fron");
# First get options (f=fast, r=baud rate divisor)
# Let's calculate the time of single bit
$bit_time = ( $opt_f ? 16 : 64 ) * ($opt_r +1);
# Open the output file
open OUTFILE,">".$opt_o or die "I can't open the output file:" . $opt_o;
#Let's print the stimulus header
print OUTFILE "stimulus asynchronous_stimulus\n";
print OUTFILE "initial_state 1\n";
print OUTFILE"start_cycle 0\n";
# Now the @ARGV should hold the pairs: time to emit the string, and string
for ($i=0;$i<=$#ARGV;$i+=2)
  {
    #The time must be monotonic
    my $new_time = $ARGV[$i];
    my $new_string = $ARGV[$i+1];
    if ( substr($new_time,0,1) eq "+" )
      {
	$sim_time=$sim_time + $new_time;
      }
    else 
      {
	if ( $new_time < $sim_time )
	  {
	    die "Time must be monotonic!!!"
	  }
	else
	  {
	    $sim_time=$new_time;
	  }
	}
    #Now we know the string emission time and the string, so let's start
    #sending
    emit_string($new_string);
  }
#Let's print the stimuli footer
print OUTFILE "name ". $opt_n ."\n";
print OUTFILE "end\n";
close OUTFILE;