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      1 /* ===-- muldc3.c - Implement __muldc3 -------------------------------------===
      2  *
      3  *                     The LLVM Compiler Infrastructure
      4  *
      5  * This file is dual licensed under the MIT and the University of Illinois Open
      6  * Source Licenses. See LICENSE.TXT for details.
      7  *
      8  * ===----------------------------------------------------------------------===
      9  *
     10  * This file implements __muldc3 for the compiler_rt library.
     11  *
     12  * ===----------------------------------------------------------------------===
     13  */
     14 
     15 #include "int_lib.h"
     16 #include "int_math.h"
     17 
     18 /* Returns: the product of a + ib and c + id */
     19 
     20 double _Complex
     21 __muldc3(double __a, double __b, double __c, double __d)
     22 {
     23     double __ac = __a * __c;
     24     double __bd = __b * __d;
     25     double __ad = __a * __d;
     26     double __bc = __b * __c;
     27     double _Complex z;
     28     __real__ z = __ac - __bd;
     29     __imag__ z = __ad + __bc;
     30     if (crt_isnan(__real__ z) && crt_isnan(__imag__ z))
     31     {
     32         int __recalc = 0;
     33         if (crt_isinf(__a) || crt_isinf(__b))
     34         {
     35             __a = crt_copysign(crt_isinf(__a) ? 1 : 0, __a);
     36             __b = crt_copysign(crt_isinf(__b) ? 1 : 0, __b);
     37             if (crt_isnan(__c))
     38                 __c = crt_copysign(0, __c);
     39             if (crt_isnan(__d))
     40                 __d = crt_copysign(0, __d);
     41             __recalc = 1;
     42         }
     43         if (crt_isinf(__c) || crt_isinf(__d))
     44         {
     45             __c = crt_copysign(crt_isinf(__c) ? 1 : 0, __c);
     46             __d = crt_copysign(crt_isinf(__d) ? 1 : 0, __d);
     47             if (crt_isnan(__a))
     48                 __a = crt_copysign(0, __a);
     49             if (crt_isnan(__b))
     50                 __b = crt_copysign(0, __b);
     51             __recalc = 1;
     52         }
     53         if (!__recalc && (crt_isinf(__ac) || crt_isinf(__bd) ||
     54                           crt_isinf(__ad) || crt_isinf(__bc)))
     55         {
     56             if (crt_isnan(__a))
     57                 __a = crt_copysign(0, __a);
     58             if (crt_isnan(__b))
     59                 __b = crt_copysign(0, __b);
     60             if (crt_isnan(__c))
     61                 __c = crt_copysign(0, __c);
     62             if (crt_isnan(__d))
     63                 __d = crt_copysign(0, __d);
     64             __recalc = 1;
     65         }
     66         if (__recalc)
     67         {
     68             __real__ z = CRT_INFINITY * (__a * __c - __b * __d);
     69             __imag__ z = CRT_INFINITY * (__a * __d + __b * __c);
     70         }
     71     }
     72     return z;
     73 }
     74