lib/muldc3.c

   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 }