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authorSzabolcs Nagy <nsz@port70.net>2013-09-03 18:50:58 +0000
committerSzabolcs Nagy <nsz@port70.net>2013-09-05 11:30:08 +0000
commitea9bb95a5b36c0a3d2ed8fb03808745b406c2633 (patch)
tree5c0d395bfff168d97c7055826a30b822eba7293b /src/math/tanl.c
parentbcd797a5ba4631c031919dad832d670e564212e9 (diff)
downloadmusl-ea9bb95a5b36c0a3d2ed8fb03808745b406c2633.tar.gz
math: long double trigonometric cleanup (cosl, sinl, sincosl, tanl)
ld128 support was added to internal kernel functions (__cosl, __sinl, __tanl, __rem_pio2l) from freebsd (not tested, but should be a good start for when ld128 arch arrives) __rem_pio2l had some code cleanup, the freebsd ld128 code seems to gather the results of a large reduction with precision loss (fixed the bug but a todo comment was added for later investigation) the old copyright was removed from the non-kernel wrapper functions (cosl, sinl, sincosl, tanl) since these are trivial and the interesting parts and comments had been already rewritten.
Diffstat (limited to 'src/math/tanl.c')
-rw-r--r--src/math/tanl.c53
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);
}