mirror of
https://github.com/jerryscript-project/jerryscript.git
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1bd1a36a81
Ubuntu 14.04 reached its end of life on April 30m 2019. Let's bump the reference to the latest LTS, which is 18.04. Ubuntu 18.04 has newer Pylint and Cppcheck, the necessary fixes and suppresses are also included in this PR. JerryScript-DCO-1.0-Signed-off-by: Csaba Osztrogonác oszi@inf.u-szeged.hu
145 lines
4.4 KiB
C
145 lines
4.4 KiB
C
/* Copyright JS Foundation and other contributors, http://js.foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* This file is based on work under the following copyright and permission
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* notice:
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*
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunSoft, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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*
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* @(#)e_acos.c 1.3 95/01/18
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*/
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#include "jerry-libm-internal.h"
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/* acos(x)
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*
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* Method:
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* acos(x) = pi/2 - asin(x)
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* acos(-x) = pi/2 + asin(x)
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* For |x|<=0.5
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* acos(x) = pi/2 - (x + x*x^2*R(x^2)) (see asin.c)
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* For x>0.5
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* acos(x) = pi/2 - (pi/2 - 2asin(sqrt((1-x)/2)))
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* = 2asin(sqrt((1-x)/2))
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* = 2s + 2s*z*R(z) ...z=(1-x)/2, s=sqrt(z)
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* = 2f + (2c + 2s*z*R(z))
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* where f=hi part of s, and c = (z-f*f)/(s+f) is the correction term
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* for f so that f+c ~ sqrt(z).
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* For x<-0.5
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* acos(x) = pi - 2asin(sqrt((1-|x|)/2))
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* = pi - 0.5*(s+s*z*R(z)), where z=(1-|x|)/2,s=sqrt(z)
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*
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* Special cases:
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* if x is NaN, return x itself;
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* if |x|>1, return NaN with invalid signal.
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*
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* Function needed: sqrt
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*/
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#define one 1.00000000000000000000e+00 /* 0x3FF00000, 0x00000000 */
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#define pi 3.14159265358979311600e+00 /* 0x400921FB, 0x54442D18 */
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#define pio2_hi 1.57079632679489655800e+00 /* 0x3FF921FB, 0x54442D18 */
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#define pio2_lo 6.12323399573676603587e-17 /* 0x3C91A626, 0x33145C07 */
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#define pS0 1.66666666666666657415e-01 /* 0x3FC55555, 0x55555555 */
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#define pS1 -3.25565818622400915405e-01 /* 0xBFD4D612, 0x03EB6F7D */
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#define pS2 2.01212532134862925881e-01 /* 0x3FC9C155, 0x0E884455 */
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#define pS3 -4.00555345006794114027e-02 /* 0xBFA48228, 0xB5688F3B */
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#define pS4 7.91534994289814532176e-04 /* 0x3F49EFE0, 0x7501B288 */
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#define pS5 3.47933107596021167570e-05 /* 0x3F023DE1, 0x0DFDF709 */
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#define qS1 -2.40339491173441421878e+00 /* 0xC0033A27, 0x1C8A2D4B */
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#define qS2 2.02094576023350569471e+00 /* 0x40002AE5, 0x9C598AC8 */
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#define qS3 -6.88283971605453293030e-01 /* 0xBFE6066C, 0x1B8D0159 */
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#define qS4 7.70381505559019352791e-02 /* 0x3FB3B8C5, 0xB12E9282 */
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double
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acos (double x)
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{
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double z, p, q, r, w, s, c;
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int hx, ix;
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hx = __HI (x);
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ix = hx & 0x7fffffff;
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if (ix >= 0x3ff00000) /* |x| >= 1 */
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{
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if (((ix - 0x3ff00000) | __LO (x)) == 0) /* |x| == 1 */
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{
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if (hx > 0) /* acos(1) = 0 */
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{
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return 0.0;
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}
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else /* acos(-1) = pi */
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{
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return pi + 2.0 * pio2_lo;
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}
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}
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return NAN; /* acos(|x|>1) is NaN */
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}
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if (ix < 0x3fe00000) /* |x| < 0.5 */
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{
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if (ix <= 0x3c600000) /* if |x| < 2**-57 */
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{
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return pio2_hi + pio2_lo;
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}
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z = x * x;
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p = z * (pS0 + z * (pS1 + z * (pS2 + z * (pS3 + z * (pS4 + z * pS5)))));
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q = one + z * (qS1 + z * (qS2 + z * (qS3 + z * qS4)));
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r = p / q;
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return pio2_hi - (x - (pio2_lo - x * r));
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}
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else if (hx < 0) /* x < -0.5 */
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{
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z = (one + x) * 0.5;
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p = z * (pS0 + z * (pS1 + z * (pS2 + z * (pS3 + z * (pS4 + z * pS5)))));
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q = one + z * (qS1 + z * (qS2 + z * (qS3 + z * qS4)));
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s = sqrt (z);
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r = p / q;
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w = r * s - pio2_lo;
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return pi - 2.0 * (s + w);
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}
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else /* x > 0.5 */
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{
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double_accessor df;
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z = (one - x) * 0.5;
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s = sqrt (z);
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df.dbl = s;
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df.as_int.lo = 0;
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c = (z - df.dbl * df.dbl) / (s + df.dbl);
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p = z * (pS0 + z * (pS1 + z * (pS2 + z * (pS3 + z * (pS4 + z * pS5)))));
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q = one + z * (qS1 + z * (qS2 + z * (qS3 + z * qS4)));
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r = p / q;
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w = r * s + c;
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return 2.0 * (df.dbl + w);
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}
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} /* acos */
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#undef one
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#undef pi
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#undef pio2_hi
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#undef pio2_lo
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#undef pS0
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#undef pS1
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#undef pS2
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#undef pS3
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#undef pS4
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#undef pS5
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#undef qS1
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#undef qS2
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#undef qS3
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#undef qS4
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