Error in accessing Hash key - perl

Question

Here's my code..I am trying to create a hash lookup table and access the data from it in every loop..
#! usr/bin/perl
use warnings;
use strict;
sub bin2dec
{
return unpack("N", pack("B32", substr("0" x 32 . shift, -32)));
}
while(<>)
{
if(/SIB_DBG/)
{
if(/TTRB:\s*([\da-f]+)\s([\da-f]+)\s([\da-f]+)\s([\da-f]+)/ ||
/ETRB:\s*([\da-f]+)\s([\da-f]+)\s([\da-f]+)\s([\da-f]+)/ ||
/Command\sETRB\s*([\da-f]+)\s([\da-f]+)\s([\da-f]+)\s([\da-f]+)/ )
{
print "$_ $1 $2 $3 $4\n";
my $deci1 = hex($1);
my $deci2 = hex($2);
my $deci3 = hex($3);
my $deci4 = hex($4);
my $bin = reverse sprintf("%032b",$deci4); #convert to 32 bit binary and reverse
print "\nbinary :$bin\n";
my $sub = substr($bin ,16,6); #extract required 6 bits
print "string :$sub\n";
my $type = bin2dec($sub);
my $val = $trb{"$type"};
print "TRB type: $type\n";
print "detail: $val\n";
}
}
}
my %trb = (
0 => "reserved",
32 => "transfer event",
48 => "vendor defined");
but I am getting an error even if I have declared trb .
Global symbol "%trb" requires explicit package name at script.plx line 31.
Execution of script.plx aborted due to compilation errors.
Again my input log file is like
Aug 31 15:25:53 usb3 kernel: [ 78.684054] SIB_DBG TTRB:00000000 00000000 00000000 00002401, PTR: ffff88005ff8b000
Aug 31 15:25:53 usb3 kernel: [ 78.815428] SIB_DBG ETRB: 5ff8b850 00000000 01000000 01018001

Answer 1

You are using the hash %trb in this line:
my $val = $trb{"$type"};
before you have declared %trb here:
my %trb = (
0 => "reserved",
32 => "transfer event",
48 => "vendor defined");
Move that declaration of %trb up above the while loop.

Answer 2

The hash %trb must be declared before it is used. Move its definition up to before the while statement -- after your subroutine defintion and all will be well
You appear to be more familiar with a different language, as you usually find Perl subroutines at the end of the program, but it doesn't matter either way