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

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/* Copyright (C) 1997, 1999, 2011 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
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#include <math.h>
#include "math_private.h"
#include "mathimpl.h"
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#ifndef SUFF
#define SUFF
#endif
#ifndef float_type
#define float_type double
#endif
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#define CONCATX(a,b) __CONCAT(a,b)
#define s(name) CONCATX(name,SUFF)
#define m81(func) __m81_u(s(func))
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float_type
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s(__ieee754_atan2) (float_type y, float_type x)
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{
float_type pi, pi_2, z;
unsigned long y_cond, x_cond;
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__asm ("fmovecr%.x %#0, %0" : "=f" (pi));
__asm ("fscale%.w %#-1, %0" : "=f" (pi_2) : "0" (pi));
y_cond = __m81_test (y);
x_cond = __m81_test (x);
if ((x_cond | y_cond) & __M81_COND_NAN)
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z = x + y;
else if (y_cond & __M81_COND_ZERO)
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{
if (x_cond & __M81_COND_NEG)
z = y_cond & __M81_COND_NEG ? -pi : pi;
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else
z = y;
}
else if (x_cond & __M81_COND_INF)
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{
if (y_cond & __M81_COND_INF)
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{
float_type pi_4;
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__asm ("fscale%.w %#-2, %0" : "=f" (pi_4) : "0" (pi));
z = x_cond & __M81_COND_NEG ? 3 * pi_4 : pi_4;
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}
else
z = x_cond & __M81_COND_NEG ? pi : 0;
if (y_cond & __M81_COND_NEG)
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z = -z;
}
else if (y_cond & __M81_COND_INF)
z = y_cond & __M81_COND_NEG ? -pi_2 : pi_2;
else if (x_cond & __M81_COND_NEG)
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{
if (y_cond & __M81_COND_NEG)
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{
if (-x > -y)
z = -pi + m81(__atan) (y / x);
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else
z = -pi_2 - m81(__atan) (x / y);
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}
else
{
if (-x > y)
z = pi + m81(__atan) (y / x);
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else
z = pi_2 - m81(__atan) (x / y);
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}
}
else
{
if (y_cond & __M81_COND_NEG)
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{
if (x > -y)
z = m81(__atan) (y / x);
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else
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z = -pi_2 - m81(__atan) (x / y);
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}
else
{
if (x > y)
z = m81(__atan) (y / x);
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else
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z = pi_2 - m81(__atan) (x / y);
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}
}
return z;
}
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strong_alias (s(__ieee754_atan2), CONCATX (s (__atan2), _finite))