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