84d9c625bf
- Fix for possible unset uid/gid in toproto - Fix for default mtree style - Update libelf - Importing libexecinfo - Resynchronize GCC, mpc, gmp, mpfr - build.sh: Replace params with show-params. This has been done as the make target has been renamed in the same way, while a new target named params has been added. This new target generates a file containing all the parameters, instead of printing it on the console. - Update test48 with new etc/services (Fix by Ben Gras <ben@minix3.org) get getservbyport() out of the inner loop Change-Id: Ie6ad5226fa2621ff9f0dee8782ea48f9443d2091
185 lines
4.9 KiB
C
185 lines
4.9 KiB
C
/*-
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* Copyright (c) 2007 Steven G. Kargl
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice unmodified, this list of conditions, and the following
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* disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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#if 0
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__FBSDID("$FreeBSD: head/lib/msun/src/e_sqrtl.c 176720 2008-03-02 01:47:58Z das $");
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#endif
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__RCSID("$NetBSD: e_sqrtl.c,v 1.4 2013/11/22 20:15:06 martin Exp $");
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#include <machine/ieee.h>
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#include <float.h>
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#include "math.h"
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#include "math_private.h"
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#ifdef __HAVE_LONG_DOUBLE
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#ifdef HAVE_FENV_H
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#include <fenv.h>
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#endif
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#ifdef LDBL_IMPLICIT_NBIT
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#define LDBL_NBIT 0
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#endif
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#ifdef HAVE_FENV_H
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/* Return (x + ulp) for normal positive x. Assumes no overflow. */
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static inline long double
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inc(long double x)
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{
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union ieee_ext_u ux = { .extu_ld = x, };
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if (++ux.extu_fracl == 0) {
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if (++ux.extu_frach == 0) {
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ux.extu_exp++;
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ux.extu_frach |= LDBL_NBIT;
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}
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}
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return (ux.extu_ld);
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}
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/* Return (x - ulp) for normal positive x. Assumes no underflow. */
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static inline long double
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dec(long double x)
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{
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union ieee_ext_u ux = { .extu_ld = x, };
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if (ux.extu_fracl-- == 0) {
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if (ux.extu_frach-- == LDBL_NBIT) {
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ux.extu_exp--;
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ux.extu_frach |= LDBL_NBIT;
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}
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}
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return (ux.extu_ld);
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}
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/*
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* This is slow, but simple and portable. You should use hardware sqrt
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* if possible.
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*/
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long double
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__ieee754_sqrtl(long double x)
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{
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union ieee_ext_u ux = { .extu_ld = x, };
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int k, r;
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long double lo, xn;
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fenv_t env;
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/* If x = NaN, then sqrt(x) = NaN. */
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/* If x = Inf, then sqrt(x) = Inf. */
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/* If x = -Inf, then sqrt(x) = NaN. */
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if (ux.extu_exp == LDBL_MAX_EXP * 2 - 1)
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return (x * x + x);
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/* If x = +-0, then sqrt(x) = +-0. */
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if ((ux.extu_frach | ux.extu_fracl | ux.extu_exp) == 0)
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return (x);
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/* If x < 0, then raise invalid and return NaN */
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if (ux.extu_sign)
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return ((x - x) / (x - x));
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feholdexcept(&env);
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if (ux.extu_exp == 0) {
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/* Adjust subnormal numbers. */
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ux.extu_ld *= 0x1.0p514;
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k = -514;
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} else {
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k = 0;
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}
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/*
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* ux.extu_ld is a normal number, so break it into ux.extu_ld = e*2^n where
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* ux.extu_ld = (2*e)*2^2k for odd n and ux.extu_ld = (4*e)*2^2k for even n.
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*/
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if ((ux.extu_exp - EXT_EXP_BIAS) & 1) { /* n is even. */
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k += ux.extu_exp - EXT_EXP_BIAS - 1; /* 2k = n - 2. */
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ux.extu_exp = EXT_EXP_BIAS + 1; /* ux.extu_ld in [2,4). */
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} else {
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k += ux.extu_exp - EXT_EXP_BIAS; /* 2k = n - 1. */
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ux.extu_exp = EXT_EXP_BIAS; /* ux.extu_ld in [1,2). */
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}
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/*
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* Newton's iteration.
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* Split ux.extu_ld into a high and low part to achieve additional precision.
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*/
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xn = sqrt(ux.extu_ld); /* 53-bit estimate of sqrtl(x). */
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#if LDBL_MANT_DIG > 100
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xn = (xn + (ux.extu_ld / xn)) * 0.5; /* 106-bit estimate. */
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#endif
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lo = ux.extu_ld;
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ux.extu_fracl = 0; /* Zero out lower bits. */
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lo = (lo - ux.extu_ld) / xn; /* Low bits divided by xn. */
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xn = xn + (ux.extu_ld / xn); /* High portion of estimate. */
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ux.extu_ld = xn + lo; /* Combine everything. */
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ux.extu_exp += (k >> 1) - 1;
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feclearexcept(FE_INEXACT);
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r = fegetround();
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fesetround(FE_TOWARDZERO); /* Set to round-toward-zero. */
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xn = x / ux.extu_ld; /* Chopped quotient (inexact?). */
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if (!fetestexcept(FE_INEXACT)) { /* Quotient is exact. */
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if (xn == ux.extu_ld) {
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fesetenv(&env);
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return (ux.extu_ld);
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}
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/* Round correctly for inputs like x = y**2 - ulp. */
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xn = dec(xn); /* xn = xn - ulp. */
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}
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if (r == FE_TONEAREST) {
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xn = inc(xn); /* xn = xn + ulp. */
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} else if (r == FE_UPWARD) {
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ux.extu_ld = inc(ux.extu_ld); /* ux.extu_ld = ux.extu_ld + ulp. */
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xn = inc(xn); /* xn = xn + ulp. */
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}
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ux.extu_ld = ux.extu_ld + xn; /* Chopped sum. */
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feupdateenv(&env); /* Restore env and raise inexact */
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ux.extu_exp--;
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return (ux.extu_ld);
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}
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#else
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/*
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* No fenv support:
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* poor man's version: just use double
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*/
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long double
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__ieee754_sqrtl(long double x)
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{
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return __ieee754_sqrt((double)x);
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}
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#endif
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#endif
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