incubator-nuttx/libs/libc/fixedmath/lib_b16cos.c

/****************************************************************************
 * libs/libc/fixedmath/lib_b16cos.c
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <fixedmath.h>

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: b16cos
 ****************************************************************************/

b16_t b16cos(b16_t rad)
{
  /* Compute cosine: sin(rad + PI/2) = cos(rad) */

  rad += b16HALFPI;
  if (rad > b16PI)
    {
      rad -= b16TWOPI;
    }

  return b16sin(rad);
}