3bc69d393d
Co-authored-by: Alan Bateman <alan.bateman@oracle.com> Co-authored-by: Alex Buckley <alex.buckley@oracle.com> Co-authored-by: Erik Joelsson <erik.joelsson@oracle.com> Co-authored-by: Jonathan Gibbons <jonathan.gibbons@oracle.com> Co-authored-by: Karen Kinnear <karen.kinnear@oracle.com> Co-authored-by: Magnus Ihse Bursie <magnus.ihse.bursie@oracle.com> Co-authored-by: Mandy Chung <mandy.chung@oracle.com> Co-authored-by: Mark Reinhold <mark.reinhold@oracle.com> Co-authored-by: Paul Sandoz <paul.sandoz@oracle.com> Reviewed-by: alanb, chegar, ihse, mduigou
60 lines
2.0 KiB
C
60 lines
2.0 KiB
C
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/*
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* Copyright (c) 1998, 2001, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/* ilogb(double x)
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* return the binary exponent of non-zero x
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* ilogb(0) = 0x80000001
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* ilogb(inf/NaN) = 0x7fffffff (no signal is raised)
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*/
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#include "fdlibm.h"
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#ifdef __STDC__
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int ilogb(double x)
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#else
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int ilogb(x)
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double x;
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#endif
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{
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int hx,lx,ix;
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hx = (__HI(x))&0x7fffffff; /* high word of x */
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if(hx<0x00100000) {
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lx = __LO(x);
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if((hx|lx)==0)
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return 0x80000001; /* ilogb(0) = 0x80000001 */
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else /* subnormal x */
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if(hx==0) {
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for (ix = -1043; lx>0; lx<<=1) ix -=1;
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} else {
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for (ix = -1022,hx<<=11; hx>0; hx<<=1) ix -=1;
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}
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return ix;
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}
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else if (hx<0x7ff00000) return (hx>>20)-1023;
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else return 0x7fffffff;
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}
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