ports/sysdeps/m68k/m680x0/fpu/e_atan2.c

   1 /* Copyright (C) 1997, 1999, 2011 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library.  If not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <math.h>
  19 #include <math_private.h>
  20 #include "mathimpl.h"
  21
  22 #ifndef SUFF
  23 #define SUFF
  24 #endif
  25 #ifndef float_type
  26 #define float_type double
  27 #endif
  28
  29 #define CONCATX(a,b) __CONCAT(a,b)
  30 #define s(name) CONCATX(name,SUFF)
  31 #define m81(func) __m81_u(s(func))
  32
  33 float_type
  34 s(__ieee754_atan2) (float_type y, float_type x)
  35 {
  36   float_type pi, pi_2, z;
  37   unsigned long y_cond, x_cond;
  38
  39   __asm ("fmovecr%.x %#0, %0" : "=f" (pi));
  40   __asm ("fscale%.w %#-1, %0" : "=f" (pi_2) : "0" (pi));
  41   y_cond = __m81_test (y);
  42   x_cond = __m81_test (x);
  43
  44   if ((x_cond | y_cond) & __M81_COND_NAN)
  45     z = x + y;
  46   else if (y_cond & __M81_COND_ZERO)
  47     {
  48       if (x_cond & __M81_COND_NEG)
  49         z = y_cond & __M81_COND_NEG ? -pi : pi;
  50       else
  51         z = y;
  52     }
  53   else if (x_cond & __M81_COND_INF)
  54     {
  55       if (y_cond & __M81_COND_INF)
  56         {
  57           float_type pi_4;
  58           __asm ("fscale%.w %#-2, %0" : "=f" (pi_4) : "0" (pi));
  59           z = x_cond & __M81_COND_NEG ? 3 * pi_4 : pi_4;
  60         }
  61       else
  62         z = x_cond & __M81_COND_NEG ? pi : 0;
  63       if (y_cond & __M81_COND_NEG)
  64         z = -z;
  65     }
  66   else if (y_cond & __M81_COND_INF)
  67     z = y_cond & __M81_COND_NEG ? -pi_2 : pi_2;
  68   else if (x_cond & __M81_COND_NEG)
  69     {
  70       if (y_cond & __M81_COND_NEG)
  71         {
  72           if (-x > -y)
  73             z = -pi + m81(__atan) (y / x);
  74           else
  75             z = -pi_2 - m81(__atan) (x / y);
  76         }
  77       else
  78         {
  79           if (-x > y)
  80             z = pi + m81(__atan) (y / x);
  81           else
  82             z = pi_2 - m81(__atan) (x / y);
  83         }
  84     }
  85   else
  86     {
  87       if (y_cond & __M81_COND_NEG)
  88         {
  89           if (x > -y)
  90             z = m81(__atan) (y / x);
  91           else
  92             z = -pi_2 - m81(__atan) (x / y);
  93         }
  94       else
  95         {
  96           if (x > y)
  97             z = m81(__atan) (y / x);
  98           else
  99             z = pi_2 - m81(__atan) (x / y);
 100         }
 101     }
 102   return z;
 103 }
 104 strong_alias (s(__ieee754_atan2), CONCATX (s (__atan2), _finite))