/*
+-------------------------------------------------------------+
| Copyright (c) 2015 Facebook, Inc. (http://www.facebook.com) |
+-------------------------------------------------------------+
*/
require 'bitwise_shift_helper.php';
error_reporting(-1);
$i32 = 1 << 31;
// if this is negative, we have a 32-bit int
$NumBitsPerInt = $i32 < 0 ? 32 : 64;
// Shift a positive value right and left
$v = 1000;
printShiftRange($v, 0, $NumBitsPerInt - 1);
// Shift a negative value right and left
$v = -1000;
printShiftRange($v, 0, $NumBitsPerInt - 1);
// Shift all kinds of scalar values to see which are ints or can be implicirly converted
$scalarValueList = array(10, -100, 0, 1.234, 0.0, TRUE, FALSE, NULL, "123", 'xx', "");
foreach ($scalarValueList as $v) {
printf("%d(%08X): >> %2d = %08X\t<< %2d = %08X\n", $v, $v, 3, $v >> 3, 5, $v << 5);
}
// Figure out the algorithm the implementations use for negative and too-large shift counts
for ($i = -129; $i <= 129; ++$i) {
$rem = $i % $NumBitsPerInt;
if ($rem == 0 || $i > 0) {
echo "{$i}, " . $rem . "\n";
} else {
$r = $NumBitsPerInt - -$i % $NumBitsPerInt;
echo "{$i}, " . $r . "\n";
}
}
<?php /* +-------------------------------------------------------------+ | Copyright (c) 2015 Facebook, Inc. (http://www.facebook.com) | +-------------------------------------------------------------+ */ require 'bitwise_shift_helper.php'; error_reporting(-1); $i32 = 1 << 31; // if this is negative, we have a 32-bit int $NumBitsPerInt = $i32 < 0 ? 32 : 64; // Shift a positive value right and left using both in- and out-of-range counts $v = 1000; printShiftRange($v, -$NumBitsPerInt - 1, -1); printShiftRange($v, $NumBitsPerInt, $NumBitsPerInt + 1); // Shift a negative value right and left using both in- and out-of-range counts $v = -1000; printShiftRange($v, -$NumBitsPerInt - 1, -1); printShiftRange($v, $NumBitsPerInt, $NumBitsPerInt + 1);