How to do unsigned 32 bit arithmetic in Perl? - perl

Question

I would like to implement the following C program in Perl:
#include <stdio.h>
#include <stdint.h>
uint32_t xorshift32 ()
{
static uint32_t y = 2463534242;
y ^= y << 13;
y ^= y >> 17;
y ^= y << 5;
return y;
}
int main (int argc, char *argv[])
{
int n = 10;
while (n-- > 0)
printf ("%u\n", xorshift32());
}
The output is:
723471715
2497366906
2064144800
2008045182
3532304609
374114282
1350636274
691148861
746858951
2653896249
This is my unsuccessful attempt:
{
package Xorshift;
use strict;
use warnings;
use integer;
sub new
{
my $class = shift;
bless { y => 2463534242 } => $class
}
sub rand ()
{
my $y = $_[0]->{y};
$y ^= $y << 13;
$y ^= $y >> 17;
$y ^= $y << 5;
$_[0]->{y} = $y;
return $y;
}
}
my $xor = Xorshift->new;
my $n = 10;
while ($n-- > 0) {
print $xor->rand(), "\n";
}
The output is this:
660888219700579
3396719463693796860
-1120433007023638100
2588568168682748299
1469630995924843144
-8422345229424035168
1449080611344244726
-4722527344582589597
8061824971057606814
-3113862584906767882
The problems:
Perl uses 64 bit arithmetic.
The integers are signed.
How to do 32 bit unsigned arithmetic instead?

Answer 1

If you want to simulate the result of 32-bit ops, you can simply apply a mask:
{
package Xorshift;
use strict;
use warnings;
use integer;
sub new
{
my $class = shift;
bless { y => 2463534242 } => $class
}
sub to32{
return ($_[0] & 0xFFFFFFFF);
}
sub rand ()
{
my $y = $_[0]->{y};
$y ^= to32($y << 13);
$y ^= to32($y >> 17);
$y ^= to32($y << 5);
$_[0]->{y} = $y;
return $y;
}
}
my $xor = Xorshift->new;
my $n = 10;
while ($n-- > 0) {
print $xor->rand(), "\n";
}