I am designing a logic simulator but stuck.

Steven_gerrard has asked for the wisdom of the Perl Monks concerning the following question:

Hi guys, Hope you guys are doing okay. I coded my first program in PERL last night and it's 'almost' ready. I am making a logic simulator which reads logic gates data from a text file and calculates the output. The text file looks something like this:

INV 1 2
BUF 5 8
AND 1 3 4
INPUT 1 5
OUTPUT 2 8
[download]

First I stored the gates (INV, BUF, AND) in an array. Then I calculated the maximum number of nets (no. of nets= 8 in this case) and assigned dummy values to the nets in the array. Then I created various routines for the gates. For some reason, the routines are just acting funnny. They work for a few cases and they wouldn't work for others. The logic routines are something like this:

#Logic Gates Routines
$t=0;
$a=0;

LAB: {

if($gate[$t] eq "INV")
{
    $mystring= @raw_data[$a];
        OUTER: while($mystring =~ m/(\d+)/g) 
            {
                print "\r\n";
                push (@new, $1);
            }
        print "\r\n";
        print @new;
        print " rerwerwe \r\n";
        $inp=$new[0];
        $out=$new[1];
        print "\r\n";
        print $net[$out-1];
        print "\r\n";
        print "$out \r\n";
        if ($net[$inp-1] eq "1")
        {
        @net[$out-1]=0;
        $gate[$t]=0;
        $t++;
        print "fef";
        last LAB;
        }
        elsif ($net[$inp-1] eq "0")
        {
        $net[$out-1]=1;
        $gate[$t]=0;
        $t++;
        last LAB;
        }
        else 
        {
        $t++;
        last LAB;
        }

}
if($gate[$t] eq "BUF")
{
    $mystring= @raw_data[$a];
        OUTER: while($mystring =~ m/(\d+)/g) 
            {
                print "\r\n";
                push (@new, $1);
            }
        print @new;
        print "\r\n";
        $inp=$new[0];
        $out=$new[1];
        if ($net[$inp-1] eq "1")
        {
        $net[$out-1]=1;
        $gate[$t]=0;
        $t++;
        last LAB;
        }
        elsif ($net[$inp-1] eq "0")
        {
        $net[$out-1]=0;
        $gate[$t]=0;
        $t++;
        last LAB;
        }
        else
        {
        $t++;
        last LAB;
        }
}

if($gate[$t] eq "AND")
{
    $mystring= @raw_data[$a];
        OUTER: while($mystring =~ m/(\d+)/g) 
            {
                print "\r\n";
                push (@new, $1);
            }
        print @new;
        print "\r\n";
        $inp1=$new[0];
        $inp2=$new[1];
        $out=$new[2];
        print $net[$inp1-1];
        $new=$net[$inp1-1];
        $new1=$net[$inp2-1];
        $new2=$net[$out-1];
        print "\r\n";
        print $net[$inp2-1];        
        print "\r\n";
        if($new == 1)
        {
            if($new1 ==1)
            {
                $net[$out-1]=1;
                print $net[$out-1];
                $gate[$t]=0;
                $t++;
                print "fesf";
                last LAB;
            }
            elsif($new1 ==0)
            {
                $net[$out-1]=0;
                print $net[$out-1];
                $gate[$t]=0;
                $t++;
                print "g";
                last LAB;
            }
            
        }
        if(($new) or ($new1) == 0)
        {
            $net[$out-1]=0;
            print $net[$out-1];
            $gate[$t]=0;
            $t++;
            last LAB;
        }
        else
        {
            print "fersf";
        }
        
}
if($gate[$t] eq "NAND")
{
        $mystring= @raw_data[$a];
        OUTER: while($mystring =~ m/(\d+)/g) 
            {
                print "\r\n";
                push (@new, $1);
            }
        print @new;
        print "\r\n";
        $inp1=$new[0];
        $inp2=$new[1];
        $out=$new[2];
        print $net[$inp1-1];
        $new=$net[$inp1-1];
        $new1=$net[$inp2-1];
        $new2=$net[$out-1];
        print "\r\n";
        print $net[$inp2-1];        
        print "\r\n";
        if($new == 1)
        {
            if($new1 ==1)
            {
                $net[$out-1]=0;
                print $net[$out-1];
                $gate[$t]=0;
                $t++;
                print "fesf";
                last LAB;
            }
            elsif($new1 ==0)
            {
                $net[$out-1]=1;
                print $net[$out-1];
                $gate[$t]=0;
                $t++;
                print "g";
                last LAB;
            }
            
        }
        if(($new) or ($new1) == 0)
        {
            $net[$out-1]=1;
            print $net[$out-1];
            $gate[$t]=0;
            $t++;
            last LAB;
        }
        else
        {
            $t++;
            last LAB;
        }
        
}
if($gate[$t] eq "OR")
{    $mystring= @raw_data[$a];
        OUTER: while($mystring =~ m/(\d+)/g) 
            {
                print "\r\n";
                push (@new, $1);
            }
        print @new;
        print "\r\n";
        $inp1=$new[0];
        $inp2=$new[1];
        $out=$new[2];
        print $net[$inp1-1];
        $new=$net[$inp1-1];
        $new1=$net[$inp2-1];
        $new2=$net[$out-1];
        print "\r\n";
        print $net[$inp2-1];        
        print "\r\n";
        if(($new)== 1)
        {
            $net[$out-1]=1;
            print $net[$out-1];
            $gate[$t]=0;
            $t++;
            last LAB;
        }
        elsif(($new1)== 1)
        {
            $net[$out-1]=1;
            print $net[$out-1];
            $gate[$t]=0;
            $t++;
            last LAB;
        }
        elsif(($new) == 0)
        {
            if(($new1) == 0)
            {
            $net[$out-1]=0;
            print $net[$out-1];
            $gate[$t]=0;
            $t++;
            last LAB;
            }
            elsif(($new1) == 1)
            {
            $net[$out-1]=1;
            print $net[$out-1];
            $gate[$t]=0;
            $t++;
            last LAB;
            }
        }
        else
        {    
            $t++;
            last LAB;
        }
        
}

if($gate[$t] eq "NOR")
{        $mystring= @raw_data[$a];
        OUTER: while($mystring =~ m/(\d+)/g) 
            {
                print "\r\n";
                push (@new, $1);
            }
        print @new;
        print "\r\n";
        $inp1=$new[0];
        $inp2=$new[1];
        $out=$new[2];
        print $net[$inp1-1];
        $new=$net[$inp1-1];
        $new1=$net[$inp2-1];
        $new2=$net[$out-1];
        print "\r\n";
        print $net[$inp2-1];        
        print "\r\n";
        if(($new)== 1)
        {
            $net[$out-1]=0;
            print $net[$out-1];
            $gate[$t]=0;
            $t++;
            last LAB;
        }
        elsif(($new1)== 1)
        {
            $net[$out-1]=0;
            print $net[$out-1];
            $gate[$t]=0;
            $t++;
            last LAB;
        }
        elsif(($new) == 0)
        {
            if(($new1) == 0)
            {
            $net[$out-1]=1;
            print $net[$out-1];
            $gate[$t]=0;
            $t++;
            last LAB;
            }
            elsif(($new1) == 1)
            {
            $net[$out-1]=0;
            print $net[$out-1];
            $gate[$t]=0;
            $t++;
            last LAB;
            }
        }
        else
        {    
            $t++;
            last LAB;
        }
        
}
}

print "@net \r\n";
print "@gate \r\n";
exit 0;
[download]

And, there's more:

At some points, the loop would work but at some point, it would just execute it even when the conditions have not been satisfied.

This is the other part of my code which is working fine.

 open(DAT, $data_file) || die("Could not open file!");
 @raw_data=<DAT>; 

$int=0;
#calculating the number of gates:
$mystring = @raw_data;
while($mystring =~ m/(\d+)/g) 
    {
    print "\r\n";
    $lines= $1;
    $lines= $lines-2;
     }
print "The number of gates is " . $lines ;
print "\r\n";
$linez=$lines+2;



#calculating the number of nets:
#max is the number of nets
$a=0;
while($a<=$linez)
{
$mystring= @raw_data[$a];
while($mystring =~ m/(\d+)/g) 
    {
     print "$1 \n";
     push(@array1, $1);
     }
print "\r\n";
my $max = max(@array1);
push(@netsize, $max);
$a++;
}
my $max = max(@netsize);  
print "\r\n";


#initializing the nets to 2
$n=0;
while ($n<=$max-1)
{
@net[$n]=2;
$n++
}

print "The net array is @net \r\n";
print "Please enter the input vectors";

#The number of inputs
$z=0;
$mystring = @raw_data[-2];
while($mystring =~ m/(\d+)/g) 
    {
    print "\r\n";
    $z++;
    }
$z--;


print "The number of inputs are $z \r\n";
print "The number of gates is $lines \r\n";
print "The number of nets are $max \r\n";
print "The number of gates are $lines \r\n";
print "Enter the inputs \r\n";


#Getting the value of the gates:
$mystring= @raw_data[-2];
while($mystring =~ m/(\d+)/g) 
    {
     print "Enter the vector for input $1 \r\n";
     $ip = <STDIN>;
     @net[$1-1]=$ip;
     }
print "\r\n";
print "@net[2] \r\n";

#pushing the gates in the array:
$b=0;
$a=0;
while($a!=$lines)
{
$mystring = @raw_data[$a];
if($mystring =~ /\A(.*?) /)
{
    print "The gate is $1";
    print "\r\n";
    @gate[$b]=$1;
    $b++;
}
$a++;
}
join(",",@gate);
join(",",@net);
print "The net array is @net \r\n";
print "The gate array is @gate \r\n";
[download]

Can you guys please help me out. Thanks already.

Comment on I am designing a logic simulator but stuck. Select or Download Code

Replies are listed 'Best First'.
Re: I am designing a logic simulator but stuck. by RichardK (Parson) on Sep 18, 2011 at 16:23 UTC
wee -- that's a lot of code to look at ;) have you used strict & warnings ? But after a quick glance, this `$mystring= @raw_data[$a];` might not be doing what you think it does. To access an element in a list try `my $str = $raw_data[$a];` As you're just starting out, you may find the articles in the Tutorials section useful :)	[reply] [d/l] [select]
Re: I am designing a logic simulator but stuck. by ww (Archbishop) on Sep 19, 2011 at 01:56 UTC
I don't know why OP's disappeared (I suspect the he deleted it after being urged to use `readmore`s or a briefer example), but just in case someone is looking for what should follow (and once did) the words "something like this: " here it is ... inside `readmore`s: Read more... (8 kB) And, there's more: At some points, the loop would work but at some point, it would just execute it even when the conditions have not been satisfied. This is the other part of my code which is working fine. Read more... (2 kB)	[reply] [d/l] [select]
Re^2: I am designing a logic simulator but stuck. by Steven_gerrard (Initiate) on Sep 19, 2011 at 04:54 UTC
I thought it was a huge code, so decided to remove it for the sake of convenience. Thanks for putting it up again.	[reply]
Re: I am designing a logic simulator but stuck. by toolic (Bishop) on Sep 18, 2011 at 23:27 UTC
Create a smaller code sample which any of us can run, give us some small input, and show us what output you expect. I am making a logic simulator For fun? Or have you a need for which the mature EDA industry hasn't provided a solution (free or otherwise). Just in case you were unaware, there are free simulators for the Verilog language, as well as the Verilog-Perl CPAN parser.	[reply]