libgcc/config/rs6000/_mulkc3.c

   1 /* Copyright (C) 1989-2021 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 #include "soft-fp.h"
  27 #include "quad-float128.h"
  28
  29 #define COPYSIGN(x,y) __builtin_copysignf128 (x, y)
  30 #define INFINITY __builtin_inff128 ()
  31 #define isnan __builtin_isnan
  32 #define isinf __builtin_isinf
  33
  34 #if defined(FLOAT128_HW_INSNS) && !defined(__mulkc3)
  35 #define __mulkc3 __mulkc3_sw
  36 #endif
  37
  38 TCtype
  39 __mulkc3 (TFtype a, TFtype b, TFtype c, TFtype d)
  40 {
  41   TFtype ac, bd, ad, bc, x, y;
  42   TCtype res;
  43
  44   ac = a * c;
  45   bd = b * d;
  46   ad = a * d;
  47   bc = b * c;
  48
  49   x = ac - bd;
  50   y = ad + bc;
  51
  52   if (isnan (x) && isnan (y))
  53     {
  54       /* Recover infinities that computed as NaN + iNaN.  */
  55       _Bool recalc = 0;
  56       if (isinf (a) || isinf (b))
  57         {
  58           /* z is infinite.  "Box" the infinity and change NaNs in
  59              the other factor to 0.  */
  60           a = COPYSIGN (isinf (a) ? 1 : 0, a);
  61           b = COPYSIGN (isinf (b) ? 1 : 0, b);
  62           if (isnan (c)) c = COPYSIGN (0, c);
  63           if (isnan (d)) d = COPYSIGN (0, d);
  64           recalc = 1;
  65         }
  66      if (isinf (c) || isinf (d))
  67         {
  68           /* w is infinite.  "Box" the infinity and change NaNs in
  69              the other factor to 0.  */
  70           c = COPYSIGN (isinf (c) ? 1 : 0, c);
  71           d = COPYSIGN (isinf (d) ? 1 : 0, d);
  72           if (isnan (a)) a = COPYSIGN (0, a);
  73           if (isnan (b)) b = COPYSIGN (0, b);
  74           recalc = 1;
  75         }
  76      if (!recalc
  77           && (isinf (ac) || isinf (bd)
  78               || isinf (ad) || isinf (bc)))
  79         {
  80           /* Recover infinities from overflow by changing NaNs to 0.  */
  81           if (isnan (a)) a = COPYSIGN (0, a);
  82           if (isnan (b)) b = COPYSIGN (0, b);
  83           if (isnan (c)) c = COPYSIGN (0, c);
  84           if (isnan (d)) d = COPYSIGN (0, d);
  85           recalc = 1;
  86         }
  87       if (recalc)
  88         {
  89           x = INFINITY * (a * c - b * d);
  90           y = INFINITY * (a * d + b * c);
  91         }
  92     }
  93
  94   __real__ res = x;
  95   __imag__ res = y;
  96   return res;
  97 }
  98