CbC/CbC_gcc: libquadmath/math/logq.c annotate

author	Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
date	Sun, 21 Aug 2011 07:07:55 +0900
parents
children	04ced10e8804

rev	line source
68 561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	1 /* logll.c
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	2 *
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	3 * Natural logarithm for 128-bit long double precision.
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	4 *
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	5 *
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	6 *
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	7 * SYNOPSIS:
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	8 *
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	9 * long double x, y, logl();
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	10 *
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	11 * y = logl( x );
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	12 *
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	13 *
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	14 *
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	15 * DESCRIPTION:
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	16 *
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	17 * Returns the base e (2.718...) logarithm of x.
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	18 *
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	19 * The argument is separated into its exponent and fractional
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	20 * parts. Use of a lookup table increases the speed of the routine.
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	21 * The program uses logarithms tabulated at intervals of 1/128 to
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	22 * cover the domain from approximately 0.7 to 1.4.
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	23 *
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	24 * On the interval [-1/128, +1/128] the logarithm of 1+x is approximated by
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	25 * log(1+x) = x - 0.5 x^2 + x^3 P(x) .
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	26 *
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	27 *
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	28 *
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	29 * ACCURACY:
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	30 *
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	31 * Relative error:
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	32 * arithmetic domain # trials peak rms
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	33 * IEEE 0.875, 1.125 100000 1.2e-34 4.1e-35
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	34 * IEEE 0.125, 8 100000 1.2e-34 4.1e-35
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	35 *
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	36 *
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	37 * WARNING:
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	38 *
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	39 * This program uses integer operations on bit fields of floating-point
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	40 * numbers. It does not work with data structures other than the
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	41 * structure assumed.
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	42 *
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	43 */
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	44
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	45 /* Copyright 2001 by Stephen L. Moshier <moshier@na-net.ornl.gov>
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	46
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	47 This library is free software; you can redistribute it and/or
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	48 modify it under the terms of the GNU Lesser General Public
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	49 License as published by the Free Software Foundation; either
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	50 version 2.1 of the License, or (at your option) any later version.
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	51
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	52 This library is distributed in the hope that it will be useful,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	53 but WITHOUT ANY WARRANTY; without even the implied warranty of
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	54 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	55 Lesser General Public License for more details.
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	56
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	57 You should have received a copy of the GNU Lesser General Public
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	58 License along with this library; if not, write to the Free Software
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	59 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	60
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	61 #include "quadmath-imp.h"
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	62
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	63 /* log(1+x) = x - .5 x^2 + x^3 l(x)
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	64 -.0078125 <= x <= +.0078125
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	65 peak relative error 1.2e-37 */
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	66 static const __float128
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	67 l3 = 3.333333333333333333333333333333336096926E-1Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	68 l4 = -2.499999999999999999999999999486853077002E-1Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	69 l5 = 1.999999999999999999999999998515277861905E-1Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	70 l6 = -1.666666666666666666666798448356171665678E-1Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	71 l7 = 1.428571428571428571428808945895490721564E-1Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	72 l8 = -1.249999999999999987884655626377588149000E-1Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	73 l9 = 1.111111111111111093947834982832456459186E-1Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	74 l10 = -1.000000000000532974938900317952530453248E-1Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	75 l11 = 9.090909090915566247008015301349979892689E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	76 l12 = -8.333333211818065121250921925397567745734E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	77 l13 = 7.692307559897661630807048686258659316091E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	78 l14 = -7.144242754190814657241902218399056829264E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	79 l15 = 6.668057591071739754844678883223432347481E-2Q;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	80
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	81 /* Lookup table of ln(t) - (t-1)
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	82 t = 0.5 + (k+26)/128)
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	83 k = 0, ..., 91 */
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	84 static const __float128 logtbl[92] = {
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	85 -5.5345593589352099112142921677820359632418E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	86 -5.2108257402767124761784665198737642086148E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	87 -4.8991686870576856279407775480686721935120E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	88 -4.5993270766361228596215288742353061431071E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	89 -4.3110481649613269682442058976885699556950E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	90 -4.0340872319076331310838085093194799765520E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	91 -3.7682072451780927439219005993827431503510E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	92 -3.5131785416234343803903228503274262719586E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	93 -3.2687785249045246292687241862699949178831E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	94 -3.0347913785027239068190798397055267411813E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	95 -2.8110077931525797884641940838507561326298E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	96 -2.5972247078357715036426583294246819637618E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	97 -2.3932450635346084858612873953407168217307E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	98 -2.1988775689981395152022535153795155900240E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	99 -2.0139364778244501615441044267387667496733E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	100 -1.8382413762093794819267536615342902718324E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	101 -1.6716169807550022358923589720001638093023E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	102 -1.5138929457710992616226033183958974965355E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	103 -1.3649036795397472900424896523305726435029E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	104 -1.2244881690473465543308397998034325468152E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	105 -1.0924898127200937840689817557742469105693E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	106 -9.6875626072830301572839422532631079809328E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	107 -8.5313926245226231463436209313499745894157E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	108 -7.4549452072765973384933565912143044991706E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	109 -6.4568155251217050991200599386801665681310E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	110 -5.5356355563671005131126851708522185605193E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	111 -4.6900728132525199028885749289712348829878E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	112 -3.9188291218610470766469347968659624282519E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	113 -3.2206394539524058873423550293617843896540E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	114 -2.5942708080877805657374888909297113032132E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	115 -2.0385211375711716729239156839929281289086E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	116 -1.5522183228760777967376942769773768850872E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	117 -1.1342191863606077520036253234446621373191E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	118 -7.8340854719967065861624024730268350459991E-4Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	119 -4.9869831458030115699628274852562992756174E-4Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	120 -2.7902661731604211834685052867305795169688E-4Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	121 -1.2335696813916860754951146082826952093496E-4Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	122 -3.0677461025892873184042490943581654591817E-5Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	123 #define ZERO logtbl[38]
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	124 0.0000000000000000000000000000000000000000E0Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	125 -3.0359557945051052537099938863236321874198E-5Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	126 -1.2081346403474584914595395755316412213151E-4Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	127 -2.7044071846562177120083903771008342059094E-4Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	128 -4.7834133324631162897179240322783590830326E-4Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	129 -7.4363569786340080624467487620270965403695E-4Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	130 -1.0654639687057968333207323853366578860679E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	131 -1.4429854811877171341298062134712230604279E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	132 -1.8753781835651574193938679595797367137975E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	133 -2.3618380914922506054347222273705859653658E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	134 -2.9015787624124743013946600163375853631299E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	135 -3.4938307889254087318399313316921940859043E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	136 -4.1378413103128673800485306215154712148146E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	137 -4.8328735414488877044289435125365629849599E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	138 -5.5782063183564351739381962360253116934243E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	139 -6.3731336597098858051938306767880719015261E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	140 -7.2169643436165454612058905294782949315193E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	141 -8.1090214990427641365934846191367315083867E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	142 -9.0486422112807274112838713105168375482480E-3Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	143 -1.0035177140880864314674126398350812606841E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	144 -1.1067990155502102718064936259435676477423E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	145 -1.2146457974158024928196575103115488672416E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	146 -1.3269969823361415906628825374158424754308E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	147 -1.4437927104692837124388550722759686270765E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	148 -1.5649743073340777659901053944852735064621E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	149 -1.6904842527181702880599758489058031645317E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	150 -1.8202661505988007336096407340750378994209E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	151 -1.9542647000370545390701192438691126552961E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	152 -2.0924256670080119637427928803038530924742E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	153 -2.2346958571309108496179613803760727786257E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	154 -2.3810230892650362330447187267648486279460E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	155 -2.5313561699385640380910474255652501521033E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	156 -2.6856448685790244233704909690165496625399E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	157 -2.8438398935154170008519274953860128449036E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	158 -3.0058928687233090922411781058956589863039E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	159 -3.1717563112854831855692484086486099896614E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	160 -3.3413836095418743219397234253475252001090E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	161 -3.5147290019036555862676702093393332533702E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	162 -3.6917475563073933027920505457688955423688E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	163 -3.8723951502862058660874073462456610731178E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	164 -4.0566284516358241168330505467000838017425E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	165 -4.2444048996543693813649967076598766917965E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	166 -4.4356826869355401653098777649745233339196E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	167 -4.6304207416957323121106944474331029996141E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	168 -4.8285787106164123613318093945035804818364E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	169 -5.0301169421838218987124461766244507342648E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	170 -5.2349964705088137924875459464622098310997E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	171 -5.4431789996103111613753440311680967840214E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	172 -5.6546268881465384189752786409400404404794E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	173 -5.8693031345788023909329239565012647817664E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	174 -6.0871713627532018185577188079210189048340E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	175 -6.3081958078862169742820420185833800925568E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	176 -6.5323413029406789694910800219643791556918E-2Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	177 -6.7595732653791419081537811574227049288168E-2Q
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	178 };
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	179
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	180 /* ln(2) = ln2a + ln2b with extended precision. */
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	181 static const __float128
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	182 ln2a = 6.93145751953125e-1Q,
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	183 ln2b = 1.4286068203094172321214581765680755001344E-6Q;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	184
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	185 __float128
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	186 logq (__float128 x)
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	187 {
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	188 __float128 z, y, w;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	189 ieee854_float128 u, t;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	190 unsigned int m;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	191 int k, e;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	192
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	193 u.value = x;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	194 m = u.words32.w0;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	195
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	196 /* Check for IEEE special cases. */
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	197 k = m & 0x7fffffff;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	198 /* log(0) = -infinity. */
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	199 if ((k \| u.words32.w1 \| u.words32.w2 \| u.words32.w3) == 0)
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	200 {
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	201 return -0.5Q / ZERO;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	202 }
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	203 /* log ( x < 0 ) = NaN */
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	204 if (m & 0x80000000)
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	205 {
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	206 return (x - x) / ZERO;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	207 }
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	208 /* log (infinity or NaN) */
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	209 if (k >= 0x7fff0000)
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	210 {
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	211 return x + x;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	212 }
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	213
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	214 /* Extract exponent and reduce domain to 0.703125 <= u < 1.40625 */
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	215 e = (int) (m >> 16) - (int) 0x3ffe;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	216 m &= 0xffff;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	217 u.words32.w0 = m \| 0x3ffe0000;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	218 m \|= 0x10000;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	219 /* Find lookup table index k from high order bits of the significand. */
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	220 if (m < 0x16800)
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	221 {
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	222 k = (m - 0xff00) >> 9;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	223 /* t is the argument 0.5 + (k+26)/128
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	224 of the nearest item to u in the lookup table. */
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	225 t.words32.w0 = 0x3fff0000 + (k << 9);
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	226 t.words32.w1 = 0;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	227 t.words32.w2 = 0;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	228 t.words32.w3 = 0;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	229 u.words32.w0 += 0x10000;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	230 e -= 1;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	231 k += 64;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	232 }
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	233 else
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	234 {
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	235 k = (m - 0xfe00) >> 10;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	236 t.words32.w0 = 0x3ffe0000 + (k << 10);
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	237 t.words32.w1 = 0;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	238 t.words32.w2 = 0;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	239 t.words32.w3 = 0;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	240 }
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	241 /* On this interval the table is not used due to cancellation error. */
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	242 if ((x <= 1.0078125Q) && (x >= 0.9921875Q))
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	243 {
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	244 z = x - 1.0Q;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	245 k = 64;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	246 t.value = 1.0Q;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	247 e = 0;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	248 }
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	249 else
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	250 {
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	251 /* log(u) = log( t u/t ) = log(t) + log(u/t)
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	252 log(t) is tabulated in the lookup table.
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	253 Express log(u/t) = log(1+z), where z = u/t - 1 = (u-t)/t.
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	254 cf. Cody & Waite. */
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	255 z = (u.value - t.value) / t.value;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	256 }
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	257 /* Series expansion of log(1+z). */
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	258 w = z * z;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	259 y = ((((((((((((l15 * z
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	260 + l14) * z
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	261 + l13) * z
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	262 + l12) * z
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	263 + l11) * z
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	264 + l10) * z
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	265 + l9) * z
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	266 + l8) * z
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	267 + l7) * z
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	268 + l6) * z
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	269 + l5) * z
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	270 + l4) * z
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	271 + l3) * z * w;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	272 y -= 0.5 * w;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	273 y += e * ln2b; /* Base 2 exponent offset times ln(2). */
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	274 y += z;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	275 y += logtbl[k-26]; /* log(t) - (t-1) */
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	276 y += (t.value - 1.0Q);
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	277 y += e * ln2a;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	278 return y;
561a7518be6b update gcc-4.6 Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp> parents: diff changeset	279 }

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561a7518be6b update gcc-4.6