hphp/runtime/base/zend/zend_multiply.h

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-2013 Facebook, Inc. (http://www.facebook.com)     |
   6    | Copyright (c) 1998-2010 Zend Technologies Ltd. (http://www.zend.com) |
   7    +----------------------------------------------------------------------+
   8    | This source file is subject to version 2.00 of the Zend license,     |
   9    | that is bundled with this package in the file LICENSE, and is        |
  10    | available through the world-wide-web at the following url:           |
  11    | http://www.zend.com/license/2_00.txt.                                |
  12    | If you did not receive a copy of the Zend license and are unable to  |
  13    | obtain it through the world-wide-web, please send a note to          |
  14    | license@zend.com so we can mail you a copy immediately.              |
  15    +----------------------------------------------------------------------+
  16 */
  17
  18 #if (defined(__x86_64__) || defined(__i386__)) && defined(__GNUC__)
  19
  20 #define ZEND_SIGNED_MULTIPLY_LONG(a, b, lval, dval, usedval) do {       \
  21     long __tmpvar;                                                      \
  22     __asm__ ("imul %3,%0\n"                                             \
  23              "adc $0,%1"                                                \
  24              : "=r"(__tmpvar),"=r"(usedval)                             \
  25              : "0"(a), "r"(b), "1"(0));                                 \
  26     if (usedval) (dval) = (double) (a) * (double) (b);                  \
  27     else (lval) = __tmpvar;                                             \
  28   } while (0)
  29
  30 #else
  31
  32 #define ZEND_SIGNED_MULTIPLY_LONG(a, b, lval, dval, usedval) do {       \
  33     long   __lres  = (a) * (b);                                         \
  34     long double __dres  = (long double)(a) * (long double)(b);          \
  35     long double __delta = (long double) __lres - __dres;                \
  36     if ( ((usedval) = (( __dres + __delta ) != __dres))) {              \
  37       (dval) = __dres;                                                  \
  38     } else {                                                            \
  39       (lval) = __lres;                                                  \
  40     }                                                                   \
  41   } while (0)
  42
  43 #endif