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Diffstat (limited to 'newlib/libm/common/cosf.c')
-rw-r--r-- | newlib/libm/common/cosf.c | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/newlib/libm/common/cosf.c b/newlib/libm/common/cosf.c new file mode 100644 index 000000000..aac0a9aee --- /dev/null +++ b/newlib/libm/common/cosf.c @@ -0,0 +1,88 @@ +/* Single-precision cos function. + Copyright (c) 2018 Arm Ltd. All rights reserved. + + 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 0.56072, maximum relative + error is 0.5303p-23. A single-step signed 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; + 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 |