diff options
Diffstat (limited to 'src/math/tanl.c')
| -rw-r--r-- | src/math/tanl.c | 53 |
1 files changed, 7 insertions, 46 deletions
diff --git a/src/math/tanl.c b/src/math/tanl.c index 546c7a02..6af06712 100644 --- a/src/math/tanl.c +++ b/src/math/tanl.c @@ -1,35 +1,3 @@ -/* 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 @@ -40,28 +8,21 @@ long double tanl(long double x) #elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384 long double tanl(long double x) { - union IEEEl2bits z; + union ldshape u = {x}; 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) { + u.i.se &= 0x7fff; + if (u.i.se == 0x7fff) + return x - x; + if (u.f < M_PI_4) { + if (u.i.se < 0x3fff - LDBL_MANT_DIG/2) { /* raise inexact if x!=0 and underflow if subnormal */ - FORCE_EVAL(z.bits.exp == 0 ? x/0x1p120f : x+0x1p120f); + FORCE_EVAL(u.i.se == 0 ? x*0x1p-120f : x+0x1p120f); return x; } return __tanl(x, 0, 0); } - n = __rem_pio2l(x, y); return __tanl(y[0], y[1], n&1); } |