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/* Single-precision cos function.
Copyright (c) 2018 Arm Ltd. All rights reserved.
SPDX-License-Identifier: BSD-3-Clause
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
3. The name of the company may not be used to endorse or promote
products derived from this software without specific prior written
permission.
THIS SOFTWARE IS PROVIDED BY ARM LTD ``AS IS'' AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
IN NO EVENT SHALL ARM LTD BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
#include "fdlibm.h"
#if !__OBSOLETE_MATH
#include <stdint.h>
#include <math.h>
#include "math_config.h"
#include "sincosf.h"
/* Fast cosf implementation. Worst-case ULP is 0.5607, maximum relative
error is 0.5303 * 2^-23. A single-step range reduction is used for
small values. Large inputs have their range reduced using fast integer
arithmetic. */
float
cosf (float y)
{
double x = y;
double s;
int n;
const sincos_t *p = &__sincosf_table[0];
if (abstop12 (y) < abstop12 (pio4))
{
double x2 = x * x;
if (unlikely (abstop12 (y) < abstop12 (0x1p-12f)))
return 1.0f;
return sinf_poly (x, x2, p, 1);
}
else if (likely (abstop12 (y) < abstop12 (120.0f)))
{
x = reduce_fast (x, p, &n);
/* Setup the signs for sin and cos. */
s = p->sign[n & 3];
if (n & 2)
p = &__sincosf_table[1];
return sinf_poly (x * s, x * x, p, n ^ 1);
}
else if (abstop12 (y) < abstop12 (INFINITY))
{
uint32_t xi = asuint (y);
int sign = xi >> 31;
x = reduce_large (xi, &n);
/* Setup signs for sin and cos - include original sign. */
s = p->sign[(n + sign) & 3];
if ((n + sign) & 2)
p = &__sincosf_table[1];
return sinf_poly (x * s, x * x, p, n ^ 1);
}
else
return __math_invalidf (y);
}
#endif
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