incubator-nuttx/libs/libc/math/lib_atan2l.c

73 lines
2.2 KiB
C

/****************************************************************************
* libs/libc/math/lib_atan2l.c
*
* This file is a part of NuttX:
*
* Copyright (C) 2012 Gregory Nutt. All rights reserved.
* Ported by: Darcy Gong
*
* It derives from the Rhombus OS math library by Nick Johnson which has
* a compatibile, MIT-style license:
*
* Copyright (C) 2009-2011 Nick Johnson <nickbjohnson4224 at gmail.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/compiler.h>
#include <math.h>
/****************************************************************************
* Public Functions
****************************************************************************/
#ifdef CONFIG_HAVE_LONG_DOUBLE
long double atan2l(long double y, long double x)
{
if (x > 0)
{
return atanl(y / x);
}
else if (y >= 0 && x < 0)
{
return atanl(y / x) + M_PI;
}
else if (y < 0)
{
if (x == 0)
{
return -M_PI_2;
}
else /* Can only be x < 0 */
{
return atanl(y / x) - M_PI;
}
}
else if (y > 0 && x == 0)
{
return M_PI_2;
}
else /* if (y == 0 && x == 0) Undefined but returns normally 0 */
{
return 0;
}
}
#endif