1 /*
   2  * Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 
  27 #include "mlib_image.h"
  28 
  29 #include <jni.h>
  30 #include "jni_util.h"
  31 
  32 /*
  33  * Declare library specific JNI_Onload entry if static build
  34  */
  35 DEF_STATIC_JNI_OnLoad
  36 
  37 /***************************************************************/
  38 typedef union {
  39   mlib_d64 db;
  40   struct {
  41 #ifdef _LITTLE_ENDIAN
  42     mlib_s32 int1, int0;
  43 #else
  44     mlib_s32 int0, int1;
  45 #endif
  46   } two_int;
  47 } type_union_mlib_d64;
  48 
  49 #define DVAIN52 4.503599627370496e15
  50 
  51 /***************************************************************/
  52 mlib_s32 mlib_ilogb(mlib_d64 X)
  53 {
  54   type_union_mlib_d64 arg;
  55   mlib_s32 n;
  56 
  57   if (X == 0.0)
  58     return -MLIB_S32_MAX;
  59   arg.db = X;
  60   n = arg.two_int.int0 & 0x7ff00000;
  61   if (n)
  62     n = (n < 0x7ff00000) ? (n >> 20) - 1023 : MLIB_S32_MAX;
  63   else {
  64     arg.db = X * DVAIN52;
  65     n = ((arg.two_int.int0 & 0x7ff00000) >> 20) - 1075;
  66   }
  67   return n;
  68 }
  69 
  70 /***************************************************************/