my $m=4; my $x=$m; $m--; my @a=(1..$m,0);
timethese(-10, {    wheel => sub {$x = $a[$x]},
                 equaland => sub {++$x==$m and $x=0},
                  mod2and => sub {$x++; $x &= $m;}
} );
Benchmark: running equaland, mod2and, wheel, each for at least 10 CPU seconds...
  equaland: 192120.20/s
   mod2and: 182722.70/s
     wheel: 170109.49/s

##</code><code>##

my $m=4; my $x=$m; $m--; my @n=(1..$m,0); my @a=();
timethese(-10, {    wheelix => sub {$a[ $x = $n[$x] ] = $x },
                 equalandix => sub {$a[ ++$x==$m and $x=0 ] = $x },
                  mod2andix => sub {$a[ ++$x, $x &= $m];}
} );
equalandix: 119200.90/s
 mod2andix: 142736.03/s
   wheelix: 130290.06/s