--- old/src/java.base/share/native/libfdlibm/e_hypot.c 2015-09-21 17:03:07.267923418 -0700 +++ /dev/null 2015-09-21 10:28:16.344267672 -0700 @@ -1,128 +0,0 @@ - -/* - * Copyright (c) 1998, 2001, Oracle and/or its affiliates. All rights reserved. - * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. - * - * This code is free software; you can redistribute it and/or modify it - * under the terms of the GNU General Public License version 2 only, as - * published by the Free Software Foundation. Oracle designates this - * particular file as subject to the "Classpath" exception as provided - * by Oracle in the LICENSE file that accompanied this code. - * - * This code is distributed in the hope that it will be useful, but WITHOUT - * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or - * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License - * version 2 for more details (a copy is included in the LICENSE file that - * accompanied this code). - * - * You should have received a copy of the GNU General Public License version - * 2 along with this work; if not, write to the Free Software Foundation, - * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. - * - * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA - * or visit www.oracle.com if you need additional information or have any - * questions. - */ - -/* __ieee754_hypot(x,y) - * - * Method : - * If (assume round-to-nearest) z=x*x+y*y - * has error less than sqrt(2)/2 ulp, than - * sqrt(z) has error less than 1 ulp (exercise). - * - * So, compute sqrt(x*x+y*y) with some care as - * follows to get the error below 1 ulp: - * - * Assume x>y>0; - * (if possible, set rounding to round-to-nearest) - * 1. if x > 2y use - * x1*x1+(y*y+(x2*(x+x1))) for x*x+y*y - * where x1 = x with lower 32 bits cleared, x2 = x-x1; else - * 2. if x <= 2y use - * t1*y1+((x-y)*(x-y)+(t1*y2+t2*y)) - * where t1 = 2x with lower 32 bits cleared, t2 = 2x-t1, - * y1= y with lower 32 bits chopped, y2 = y-y1. - * - * NOTE: scaling may be necessary if some argument is too - * large or too tiny - * - * Special cases: - * hypot(x,y) is INF if x or y is +INF or -INF; else - * hypot(x,y) is NAN if x or y is NAN. - * - * Accuracy: - * hypot(x,y) returns sqrt(x^2+y^2) with error less - * than 1 ulps (units in the last place) - */ - -#include "fdlibm.h" - -#ifdef __STDC__ - double __ieee754_hypot(double x, double y) -#else - double __ieee754_hypot(x,y) - double x, y; -#endif -{ - double a=x,b=y,t1,t2,y1,y2,w; - int j,k,ha,hb; - - ha = __HI(x)&0x7fffffff; /* high word of x */ - hb = __HI(y)&0x7fffffff; /* high word of y */ - if(hb > ha) {a=y;b=x;j=ha; ha=hb;hb=j;} else {a=x;b=y;} - __HI(a) = ha; /* a <- |a| */ - __HI(b) = hb; /* b <- |b| */ - if((ha-hb)>0x3c00000) {return a+b;} /* x/y > 2**60 */ - k=0; - if(ha > 0x5f300000) { /* a>2**500 */ - if(ha >= 0x7ff00000) { /* Inf or NaN */ - w = a+b; /* for sNaN */ - if(((ha&0xfffff)|__LO(a))==0) w = a; - if(((hb^0x7ff00000)|__LO(b))==0) w = b; - return w; - } - /* scale a and b by 2**-600 */ - ha -= 0x25800000; hb -= 0x25800000; k += 600; - __HI(a) = ha; - __HI(b) = hb; - } - if(hb < 0x20b00000) { /* b < 2**-500 */ - if(hb <= 0x000fffff) { /* subnormal b or 0 */ - if((hb|(__LO(b)))==0) return a; - t1=0; - __HI(t1) = 0x7fd00000; /* t1=2^1022 */ - b *= t1; - a *= t1; - k -= 1022; - } else { /* scale a and b by 2^600 */ - ha += 0x25800000; /* a *= 2^600 */ - hb += 0x25800000; /* b *= 2^600 */ - k -= 600; - __HI(a) = ha; - __HI(b) = hb; - } - } - /* medium size a and b */ - w = a-b; - if (w>b) { - t1 = 0; - __HI(t1) = ha; - t2 = a-t1; - w = sqrt(t1*t1-(b*(-b)-t2*(a+t1))); - } else { - a = a+a; - y1 = 0; - __HI(y1) = hb; - y2 = b - y1; - t1 = 0; - __HI(t1) = ha+0x00100000; - t2 = a - t1; - w = sqrt(t1*y1-(w*(-w)-(t1*y2+t2*b))); - } - if(k!=0) { - t1 = 1.0; - __HI(t1) += (k<<20); - return t1*w; - } else return w; -}