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_mulkc3.c revision 1.1.1.1.4.1 
      1 /* Copyright (C) 1989-2017 Free Software Foundation, Inc.
      2 
      3 This file is part of GCC.
      4 
      5 GCC is free software; you can redistribute it and/or modify it under
      6 the terms of the GNU General Public License as published by the Free
      7 Software Foundation; either version 3, or (at your option) any later
      8 version.
      9 
     10 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
     11 WARRANTY; without even the implied warranty of MERCHANTABILITY or
     12 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
     13 for more details.
     14 
     15 Under Section 7 of GPL version 3, you are granted additional
     16 permissions described in the GCC Runtime Library Exception, version
     17 3.1, as published by the Free Software Foundation.
     18 
     19 You should have received a copy of the GNU General Public License and
     20 a copy of the GCC Runtime Library Exception along with this program;
     21 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
     22 <http://www.gnu.org/licenses/>.  */
     23 
     24 /* This is a temporary specialization of code from libgcc/libgcc2.c.  */
     25 
     26 typedef float KFtype __attribute__ ((mode (KF)));
     27 typedef __complex float KCtype __attribute__ ((mode (KC)));
     28 
     29 #define COPYSIGN(x,y) __builtin_copysignq (x, y)
     30 #define INFINITY __builtin_infq ()
     31 #define isnan __builtin_isnan
     32 #define isinf __builtin_isinf
     33 
     34 KCtype
     35 __mulkc3 (KFtype a, KFtype b, KFtype c, KFtype d)
     36 {
     37   KFtype ac, bd, ad, bc, x, y;
     38   KCtype res;
     39 
     40   ac = a * c;
     41   bd = b * d;
     42   ad = a * d;
     43   bc = b * c;
     44 
     45   x = ac - bd;
     46   y = ad + bc;
     47 
     48   if (isnan (x) && isnan (y))
     49     {
     50       /* Recover infinities that computed as NaN + iNaN.  */
     51       _Bool recalc = 0;
     52       if (isinf (a) || isinf (b))
     53 	{
     54 	  /* z is infinite.  "Box" the infinity and change NaNs in
     55 	     the other factor to 0.  */
     56 	  a = COPYSIGN (isinf (a) ? 1 : 0, a);
     57 	  b = COPYSIGN (isinf (b) ? 1 : 0, b);
     58 	  if (isnan (c)) c = COPYSIGN (0, c);
     59 	  if (isnan (d)) d = COPYSIGN (0, d);
     60           recalc = 1;
     61 	}
     62      if (isinf (c) || isinf (d))
     63 	{
     64 	  /* w is infinite.  "Box" the infinity and change NaNs in
     65 	     the other factor to 0.  */
     66 	  c = COPYSIGN (isinf (c) ? 1 : 0, c);
     67 	  d = COPYSIGN (isinf (d) ? 1 : 0, d);
     68 	  if (isnan (a)) a = COPYSIGN (0, a);
     69 	  if (isnan (b)) b = COPYSIGN (0, b);
     70 	  recalc = 1;
     71 	}
     72      if (!recalc
     73 	  && (isinf (ac) || isinf (bd)
     74 	      || isinf (ad) || isinf (bc)))
     75 	{
     76 	  /* Recover infinities from overflow by changing NaNs to 0.  */
     77 	  if (isnan (a)) a = COPYSIGN (0, a);
     78 	  if (isnan (b)) b = COPYSIGN (0, b);
     79 	  if (isnan (c)) c = COPYSIGN (0, c);
     80 	  if (isnan (d)) d = COPYSIGN (0, d);
     81 	  recalc = 1;
     82 	}
     83       if (recalc)
     84 	{
     85 	  x = INFINITY * (a * c - b * d);
     86 	  y = INFINITY * (a * d + b * c);
     87 	}
     88     }
     89 
     90   __real__ res = x;
     91   __imag__ res = y;
     92   return res;
     93 }
     94 
     95