mirror of
https://github.com/fluencelabs/musl
synced 2025-05-19 02:31:29 +00:00
bfda379358
* use unsigned arithmetics * use unsigned to store arg reduction quotient (so n&3 is understood) * remove z=0.0 variables, use literal 0 * raise underflow and inexact exceptions properly when x is small * fix spurious underflow in tanl
69 lines
2.3 KiB
C
69 lines
2.3 KiB
C
/* origin: FreeBSD /usr/src/lib/msun/src/s_tanl.c */
|
|
/*-
|
|
* Copyright (c) 2007 Steven G. Kargl
|
|
* 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 unmodified, 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.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 THE AUTHOR 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.
|
|
*/
|
|
/*
|
|
* Limited testing on pseudorandom numbers drawn within [0:4e8] shows
|
|
* an accuracy of <= 1.5 ULP where 247024 values of x out of 40 million
|
|
* possibles resulted in tan(x) that exceeded 0.5 ULP (ie., 0.6%).
|
|
*/
|
|
|
|
#include "libm.h"
|
|
|
|
#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
|
|
long double tanl(long double x)
|
|
{
|
|
return tan(x);
|
|
}
|
|
#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
|
|
long double tanl(long double x)
|
|
{
|
|
union IEEEl2bits z;
|
|
long double y[2];
|
|
unsigned n;
|
|
|
|
z.e = x;
|
|
z.bits.sign = 0;
|
|
|
|
/* If x = NaN or Inf, then tan(x) = NaN. */
|
|
if (z.bits.exp == 0x7fff)
|
|
return (x - x) / (x - x);
|
|
|
|
/* |x| < (double)pi/4 */
|
|
if (z.e < M_PI_4) {
|
|
/* |x| < 0x1p-64 */
|
|
if (z.bits.exp < 0x3fff - 64) {
|
|
/* raise inexact if x!=0 and underflow if subnormal */
|
|
FORCE_EVAL(z.bits.exp == 0 ? x/0x1p120f : x+0x1p120f);
|
|
return x;
|
|
}
|
|
return __tanl(x, 0, 0);
|
|
}
|
|
|
|
n = __rem_pio2l(x, y);
|
|
return __tanl(y[0], y[1], n&1);
|
|
}
|
|
#endif
|