As shown in the code . I have taken a hex number converted to binary , added it to an array and reshuffled .

I want to convert it back to hex and stuck at the step where converting the array to a variable and then to hexa. I have used couple of steps which I comented and they didn't work. Is there a way to convert an array to variable and then to hex for my case

    #!/usr/bin/env perl
    
    use warnings;
    import math 
    
    
    my $value =  hex ( 'FE300B0' );
    
    print "Dec: ",$value,"\n";
    printf ( "Hex: %X\n", $value );
    my $binval = sprintf ( "%0*b\n",32, $value );
    
    print $binval;
    my @binval_arr = split('', $binval, 32);
    #print "Size: ",scalar @binval_arr,"\n";
    
    #print "\$binval_arr[27] = $binval_arr[27]\n";
    print @binval_arr;
    #my @mod_bin = @binval_arr;
    #my @mod_bin;
    my @mod_bin = (0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0);
     
  #modifeid 20..31   
      @mod_bin[20..31] = @binval_arr[20..31];
      @mod_bin[9] = $binval_arr[10];
      @mod_bin[18,19] = @binval_arr[14,15];
      @mod_bin[10..17] = @binval_arr[2..9];
     
    #print join("\n",@binval_arr),"\n";
    print @mod_bin,"\n";
    #my $mod_str = join('', @mod_bin);
    #print $mod_str,"\n";
    
    my $mod_int = int(@mod_bin);
    my $mod_int = \@mod_bin;
    print $mod_int,"\n";


   output :: 
    Dec: 266535088
Hex: FE300B0
00001111111000110000000010110000
00001111111000110000000010110000
00000000010011111111000010110000
ARRAY(0x5635e48dcca8)

CodePudding user response：

You shouldn't be converting to/from binary at all. You should be using bit arithmetic operators.

my $value = hex( 'FE300B0' );

my $modified =
     ( ( $value >>  2 ) & 0x0FFF ) <<  2
   | ( ( $value >> 21 ) & 0x0001 ) << 22
   | ( ( $value >> 16 ) & 0x0003 ) << 12
   | ( ( $value >> 22 ) & 0x00FF ) << 14;

Note that this assigns to bit 13 ($mod_bin[18] in the original) twice, just like your code. This is surely a mistake?

CodePudding user response：

One way to do the binary to hex operation is:

$hex = sprintf "%x", oct("0b$binary");

To convert an array of "0" and "1" elements into a 32-character scalar of "0" and "1" characters, use

$binary = join("", @mod_bin);

CodePudding user response：

Complete code which works as intended. This was to reshuffle bits inside a 32 bit addrs for internal use in Dept of CPU registers . There may be easy ways in Perl than this lengthy code .

#!/usr/bin/env perl

use warnings;
import math 


my $value =  hex (FE300B0);

print "Dec: ",$value,"\n";
printf ( "Hex: %X\n", $value );
my $binval = sprintf ( "%0*b\n",32, $value );

print $binval;
my @binval_arr = split('', $binval, 32);
#print "Size: ",scalar @binval_arr,"\n";

#print "\$binval_arr[27] = $binval_arr[27]\n";
print @binval_arr;
#my @mod_bin = @binval_arr;
#my @mod_bin;
my @mod_bin = (0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0);
 
 @mod_bin[20..31] = @binval_arr[20..31];
 @mod_bin[9] = $binval_arr[10];
 @mod_bin[18,19] = @binval_arr[14,15];
 @mod_bin[10..17] = @binval_arr[2..9];
 
 
#print join("\n",@binval_arr),"\n";
print @mod_bin,"\n";
my $mod_str = join('', @mod_bin);
#print $mod_str,"\n";

#my $mod_int = int(@mod_bin);
#my $mod_int = \@mod_bin;
#print $mod_int,"\n";

my $mod_hex = sprintf "%x", oct("0b$mod_str");

print $mod_hex,"\n";