#38045 [NEW]: Integer mathematics problem

From: igor at oleinikov dot ru Operating system: FreeBSD 6.1 Release PHP version: 5.1.4 PHP Bug Type: Scripting Engine problem Bug description: Integer mathematics problem Description: ------------ When I want to calculate integer summ of two integers with overflow, I get unexpected result, becouse result converts to float, then converts to integer. Important: I've tested this example on two systems with same versions of php (5.1.4) and different versions of freebsd (4.11 and 6.1). On last operation [$b = (int)($a + $a)], freebsd 4.11 produce expected result: int(0), but freebsd 6.1 produce minimal integer (-2147483648). How can I implement algorithm with integer mathematics, that requires overflows? i have it successfully working on freebsd 4.11, but it don't work on freebsd 6.1 (( Reproduce code: --------------- $a = 0x80000000; //i'd like it would integer, but it float ;) var_dump($a, dechex($a)); $a = (int)0x80000000; //ok, i'll make it integer myself var_dump($a, dechex($a)); $b = $a + $a; //int + int = int ? var_dump($b, dechex($b)); $b = (int)($a + $a); var_dump($b, dechex($b)); Expected result: ---------------- int(-2147483648) string(8) "80000000" int(-2147483648) string(8) "80000000" int(0) string(8) "0" //expected, int + int = int with overflow int(0) string(8) "0" //expected, conversion with overflow Actual result: -------------- float(2147483648) string(8) "80000000" // expected int int(-2147483648) string(8) "80000000" // when I convert to int myself float(-4294967296) string(8) "80000000" //expected int, but it overflows and converts to float int(-2147483648) string(8) "80000000" -- Edit bug report at http://bugs.php.net/?id=38045&edit=1 -- Try a CVS snapshot (PHP 4.4): http://bugs.php.net/fix.php?id=38045&r=trysnapshot44 Try a CVS snapshot (PHP 5.2): http://bugs.php.net/fix.php?id=38045&r=trysnapshot52 Try a CVS snapshot (PHP 6.0): http://bugs.php.net/fix.php?id=38045&r=trysnapshot60 Fixed in CVS: http://bugs.php.net/fix.php?id=38045&r=fixedcvs Fixed in release: http://bugs.php.net/fix.php?id=38045&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=38045&r=needtrace Need Reproduce Script: http://bugs.php.net/fix.php?id=38045&r=needscript Try newer version: http://bugs.php.net/fix.php?id=38045&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=38045&r=support Expected behavior: http://bugs.php.net/fix.php?id=38045&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=38045&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=38045&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=38045&r=globals PHP 3 support discontinued: http://bugs.php.net/fix.php?id=38045&r=php3 Daylight Savings: http://bugs.php.net/fix.php?id=38045&r=dst IIS Stability: http://bugs.php.net/fix.php?id=38045&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=38045&r=gnused Floating point limitations: http://bugs.php.net/fix.php?id=38045&r=float No Zend Extensions: http://bugs.php.net/fix.php?id=38045&r=nozend MySQL Configuration Error: http://bugs.php.net/fix.php?id=38045&r=mysqlcfg