diff --git a/phpseclib/Crypt/Base.php b/phpseclib/Crypt/Base.php
index c1cd98d9..25dba257 100644
--- a/phpseclib/Crypt/Base.php
+++ b/phpseclib/Crypt/Base.php
@@ -529,6 +529,38 @@ class Crypt_Base
         if ($this->use_inline_crypt !== false) {
             $this->use_inline_crypt = version_compare(PHP_VERSION, '5.3.0') >= 0 || function_exists('create_function');
         }
+
+        if (!defined('CRYPT_BASE_USE_SAFE_INTVAL')) {
+            switch (true) {
+                // PHP 5.3, per http://php.net/releases/5_3_0.php, introduced "more consistent float rounding"
+                case version_compare(PHP_VERSION, '5.3.0') >= 0 && (php_uname('m') & "\xDF\xDF\xDF") != 'ARM':
+                // PHP_OS & "\xDF\xDF\xDF" == strtoupper(substr(PHP_OS, 0, 3)), but a lot faster
+                case (PHP_OS & "\xDF\xDF\xDF") === 'WIN':
+                case defined('PHP_INT_SIZE') && PHP_INT_SIZE == 8:
+                    define('CRYPT_BASE_USE_SAFE_INTVAL', false);
+                    break;
+                case (php_uname('m') & "\xDF\xDF\xDF") == 'ARM':
+                    switch (true) {
+                        // PHP_VERSION_ID wasn't a constant until PHP 5.2.7
+                        case version_compare(PHP_VERSION, '5.3.0') < 1:
+                        /* PHP 7.0.0 introduced a bug that affected 32-bit ARM processors:
+
+                           https://github.com/php/php-src/commit/716da71446ebbd40fa6cf2cea8a4b70f504cc3cd
+
+                           altho the changelogs make no mention of it, this bug was fixed with this commit:
+
+                           https://github.com/php/php-src/commit/c1729272b17a1fe893d1a54e423d3b71470f3ee8
+
+                           affected versions of PHP are: 7.0.x, 7.1.0 - 7.1.23 and 7.2.0 - 7.2.11 */
+                        case PHP_VERSION_ID >= 70000 && PHP_VERSION_ID <= 70123:
+                        case PHP_VERSION_ID >= 70200 && PHP_VERSION_ID <= 70211:
+                            define('CRYPT_BASE_USE_SAFE_INTVAL', true);
+                            break;
+                        default:
+                            define('CRYPT_BASE_USE_SAFE_INTVAL', false);
+                    }
+            }
+        }
     }
 
     /**
@@ -2647,32 +2679,8 @@ class Crypt_Base
      */
     function safe_intval($x)
     {
-        switch (true) {
-            case is_int($x):
-            // PHP 5.3, per http://php.net/releases/5_3_0.php, introduced "more consistent float rounding"
-            case version_compare(PHP_VERSION, '5.3.0') >= 0 && (php_uname('m') & "\xDF\xDF\xDF") != 'ARM':
-            // PHP_OS & "\xDF\xDF\xDF" == strtoupper(substr(PHP_OS, 0, 3)), but a lot faster
-            case (PHP_OS & "\xDF\xDF\xDF") === 'WIN':
-                return $x;
-            case (php_uname('m') & "\xDF\xDF\xDF") == 'ARM':
-                switch (true) {
-                    // PHP_VERSION_ID wasn't a constant until PHP 5.2.7
-                    case version_compare(PHP_VERSION, '5.3.0') < 1:
-                    /* PHP 7.0.0 introduced a bug that affected 32-bit ARM processors:
-
-                       https://github.com/php/php-src/commit/716da71446ebbd40fa6cf2cea8a4b70f504cc3cd
-
-                       altho the changelogs make no mention of it, this bug was fixed with this commit:
-
-                       https://github.com/php/php-src/commit/c1729272b17a1fe893d1a54e423d3b71470f3ee8
-
-                       affected versions of PHP are: 7.0.x, 7.1.0 - 7.1.23 and 7.2.0 - 7.2.11 */
-                    case PHP_VERSION_ID >= 70000 && PHP_VERSION_ID <= 70123:
-                    case PHP_VERSION_ID >= 70200 && PHP_VERSION_ID <= 70211:
-                        break;
-                    default:
-                        return $x;
-                }
+        if (CRYPT_BASE_USE_SAFE_INTVAL || is_int($x)) {
+            return $x;
         }
         return (fmod($x, 0x80000000) & 0x7FFFFFFF) |
             ((fmod(floor($x / 0x80000000), 2) & 1) << 31);
@@ -2686,26 +2694,12 @@ class Crypt_Base
      */
     function safe_intval_inline()
     {
-        // on 32-bit linux systems with PHP < 5.3 float to integer conversion is bad
-        switch (true) {
-            case defined('PHP_INT_SIZE') && PHP_INT_SIZE == 8:
-            case version_compare(PHP_VERSION, '5.3.0') >= 0 && (php_uname('m') & "\xDF\xDF\xDF") != 'ARM':
-            case (PHP_OS & "\xDF\xDF\xDF") === 'WIN':
-                return '%s';
-                break;
-            case (php_uname('m') & "\xDF\xDF\xDF") == 'ARM':
-                switch (true) {
-                    case version_compare(PHP_VERSION, '5.3.0') < 1:
-                    case PHP_VERSION_ID >= 70000 && PHP_VERSION_ID <= 70123:
-                    case PHP_VERSION_ID >= 70200 && PHP_VERSION_ID <= 70211:
-                        break;
-                    default:
-                        return '%s';
-                }
-            default:
-                $safeint = '(is_int($temp = %s) ? $temp : (fmod($temp, 0x80000000) & 0x7FFFFFFF) | ';
-                return $safeint . '((fmod(floor($temp / 0x80000000), 2) & 1) << 31))';
+        if (CRYPT_BASE_USE_SAFE_INTVAL) {
+            return '%s';
         }
+
+        $safeint = '(is_int($temp = %s) ? $temp : (fmod($temp, 0x80000000) & 0x7FFFFFFF) | ';
+        return $safeint . '((fmod(floor($temp / 0x80000000), 2) & 1) << 31))';
     }
 
     /**