glibc/sysdeps/m68k/fpu/e_atan2.c
Ulrich Drepper 57a52ec851 Rewritten.
1997-03-25 01:31:06 +00:00

99 lines
2.4 KiB
C

/* Copyright (C) 1997 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#define __LIBC_M81_MATH_INLINES
#include <math.h>
#include "math_private.h"
#ifndef SUFF
#define SUFF
#endif
#ifndef float_type
#define float_type double
#endif
#define __CONCATX(a,b) __CONCAT(a,b)
float_type
__CONCATX(__ieee754_atan2,SUFF) (float_type y, float_type x)
{
float_type pi, pi_2, z;
__asm ("fmovecr%.x %#0, %0" : "=f" (pi));
__asm ("fscale%.w %#-1, %0" : "=f" (pi_2) : "0" (pi));
if (x != x || y != y)
z = x + y;
else if (y == 0)
{
if (signbit (x))
z = signbit (y) ? -pi : pi;
else
z = y;
}
else if (__m81_u(__CONCATX(__isinf,SUFF)) (x))
{
if (__m81_u(__CONCATX(__isinf,SUFF)) (y))
{
float_type pi_4;
__asm ("fscale%.w %#-1, %0" : "=f" (pi_4) : "0" (pi_2));
z = x > 0 ? pi_4 : 3 * pi_4;
}
else
z = x > 0 ? 0 : pi;
if (signbit (y))
z = -z;
}
else if (__m81_u(__CONCATX(__isinf,SUFF)) (y))
z = y > 0 ? pi_2 : -pi_2;
else if (x > 0)
{
if (y > 0)
{
if (x > y)
z = __m81_u(__CONCATX(__atan,SUFF)) (y / x);
else
z = pi_2 - __m81_u(__CONCATX(__atan,SUFF)) (x / y);
}
else
{
if (x > -y)
z = __m81_u(__CONCATX(__atan,SUFF)) (y / x);
else
z = -pi_2 - __m81_u(__CONCATX(__atan,SUFF)) (x / y);
}
}
else
{
if (y < 0)
{
if (-x > y)
z = -pi + __m81_u(__CONCATX(__atan,SUFF)) (y / x);
else
z = -pi_2 - __m81_u(__CONCATX(__atan,SUFF)) (x / y);
}
else
{
if (-x > y)
z = pi + __m81_u(__CONCATX(__atan,SUFF)) (y / x);
else
z = pi_2 - __m81_u(__CONCATX(__atan,SUFF)) (x / y);
}
}
return z;
}