src/compiler-rt/lib/builtins/multc3.c

   1 /* ===-- multc3.c - Implement __multc3 -------------------------------------===
   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 __multc3 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 COMPILER_RT_ABI long double _Complex
  21 __multc3(long double a, long double b, long double c, long double d)
  22 {
  23     long double ac = a * c;
  24     long double bd = b * d;
  25     long double ad = a * d;
  26     long double bc = b * c;
  27     long double _Complex z;
  28     __real__ z = ac - bd;
  29     __imag__ z = ad + bc;
  30     if (crt_isnan(__real__ z) && crt_isnan(__imag__ z)) {
  31         int recalc = 0;
  32         if (crt_isinf(a) || crt_isinf(b)) {
  33             a = crt_copysignl(crt_isinf(a) ? 1 : 0, a);
  34             b = crt_copysignl(crt_isinf(b) ? 1 : 0, b);
  35             if (crt_isnan(c))
  36                 c = crt_copysignl(0, c);
  37             if (crt_isnan(d))
  38                 d = crt_copysignl(0, d);
  39             recalc = 1;
  40         }
  41         if (crt_isinf(c) || crt_isinf(d)) {
  42             c = crt_copysignl(crt_isinf(c) ? 1 : 0, c);
  43             d = crt_copysignl(crt_isinf(d) ? 1 : 0, d);
  44             if (crt_isnan(a))
  45                 a = crt_copysignl(0, a);
  46             if (crt_isnan(b))
  47                 b = crt_copysignl(0, b);
  48             recalc = 1;
  49         }
  50         if (!recalc && (crt_isinf(ac) || crt_isinf(bd) ||
  51                           crt_isinf(ad) || crt_isinf(bc))) {
  52             if (crt_isnan(a))
  53                 a = crt_copysignl(0, a);
  54             if (crt_isnan(b))
  55                 b = crt_copysignl(0, b);
  56             if (crt_isnan(c))
  57                 c = crt_copysignl(0, c);
  58             if (crt_isnan(d))
  59                 d = crt_copysignl(0, d);
  60             recalc = 1;
  61         }
  62         if (recalc) {
  63             __real__ z = CRT_INFINITY * (a * c - b * d);
  64             __imag__ z = CRT_INFINITY * (a * d + b * c);
  65         }
  66     }
  67     return z;
  68 }