libgcc/config/rs6000/_mulkc3.c

   1 /* Copyright (C) 1989-2024 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 /* Use the correct built-in function based on whether TFmode is _Float128 or
  30    long double.  See quad-float128.h for more details.  */
  31 #ifndef __LONG_DOUBLE_IEEE128__
  32 #define COPYSIGN(x,y) __builtin_copysignf128 (x, y)
  33 #define INFINITY __builtin_inff128 ()
  34
  35 #else
  36 #define COPYSIGN(x,y) __builtin_copysignl (x, y)
  37 #define INFINITY __builtin_infl ()
  38 #endif
  39
  40 #define isnan __builtin_isnan
  41 #define isinf __builtin_isinf
  42
  43 #if defined(FLOAT128_HW_INSNS) && !defined(__mulkc3)
  44 #define __mulkc3 __mulkc3_sw
  45 #endif
  46
  47 TCtype
  48 __mulkc3 (TFtype a, TFtype b, TFtype c, TFtype d)
  49 {
  50   TFtype ac, bd, ad, bc, x, y;
  51   TCtype res;
  52
  53   ac = a * c;
  54   bd = b * d;
  55   ad = a * d;
  56   bc = b * c;
  57
  58   x = ac - bd;
  59   y = ad + bc;
  60
  61   if (isnan (x) && isnan (y))
  62     {
  63       /* Recover infinities that computed as NaN + iNaN.  */
  64       _Bool recalc = 0;
  65       if (isinf (a) || isinf (b))
  66         {
  67           /* z is infinite.  "Box" the infinity and change NaNs in
  68              the other factor to 0.  */
  69           a = COPYSIGN (isinf (a) ? 1 : 0, a);
  70           b = COPYSIGN (isinf (b) ? 1 : 0, b);
  71           if (isnan (c)) c = COPYSIGN (0, c);
  72           if (isnan (d)) d = COPYSIGN (0, d);
  73           recalc = 1;
  74         }
  75      if (isinf (c) || isinf (d))
  76         {
  77           /* w is infinite.  "Box" the infinity and change NaNs in
  78              the other factor to 0.  */
  79           c = COPYSIGN (isinf (c) ? 1 : 0, c);
  80           d = COPYSIGN (isinf (d) ? 1 : 0, d);
  81           if (isnan (a)) a = COPYSIGN (0, a);
  82           if (isnan (b)) b = COPYSIGN (0, b);
  83           recalc = 1;
  84         }
  85      if (!recalc
  86           && (isinf (ac) || isinf (bd)
  87               || isinf (ad) || isinf (bc)))
  88         {
  89           /* Recover infinities from overflow by changing NaNs to 0.  */
  90           if (isnan (a)) a = COPYSIGN (0, a);
  91           if (isnan (b)) b = COPYSIGN (0, b);
  92           if (isnan (c)) c = COPYSIGN (0, c);
  93           if (isnan (d)) d = COPYSIGN (0, d);
  94           recalc = 1;
  95         }
  96       if (recalc)
  97         {
  98           x = INFINITY * (a * c - b * d);
  99           y = INFINITY * (a * d + b * c);
 100         }
 101     }
 102
 103   __real__ res = x;
 104   __imag__ res = y;
 105   return res;
 106 }
 107