An example of reversing bits in a 32-bit number

ReversingBits.ps1

function reverse(){
    param([Int32]$b)
    $b = (($b -band 0xf0) -shr 4) -bor (($b -band 0x0f) -shl 4)
    $b = (($b -band 0xcc) -shr 2) -bor (($b -band 0x33) -shl 2)
    $b = (($b -band 0xaa) -shr 1) -bor (($b -band 0x55) -shl 1)
    $b
}
# on a 64bit machine this is an alternative to reverse() function
function reverse64(){
    param([Int32]$x)
    $x = ($x * 0x0202020202 -band 0x010884422010) % 1023
    $x
}

$in = 0x04c11db7

$byte0 = ($in -band 0xff)
$byte1 = ($in -band 0xff00) -shr 8
$byte2 = ($in -band 0xff0000) -shr 16
$byte3 = ($in -band 0xff000000) -shr 24

$out = ((reverse $byte0) -shl 24 ) -bor ((reverse $byte1) -shl 16 ) -bor ((reverse $byte2) -shl 8 ) -bor (reverse $byte3 )

"{0:X0}" -f $out