newlib/libm/ld/s_frexpl.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2004-2005 David Schultz <das@FreeBSD.ORG>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  *
  28  * $FreeBSD$
  29  */
  30
  31 #include <float.h>
  32 #include <math.h>
  33
  34 #include "fpmath.h"
  35
  36 #if LDBL_MAX_EXP != 0x4000
  37 #error "Unsupported long double format"
  38 #endif
  39
  40 long double
  41 frexpl(long double x, int *ex)
  42 {
  43         union IEEEl2bits u;
  44
  45         u.e = x;
  46         switch (u.bits.exp) {
  47         case 0:         /* 0 or subnormal */
  48                 if ((u.bits.manl | u.bits.manh) == 0) {
  49                         *ex = 0;
  50                 } else {
  51                         u.e *= 0x1.0p514;
  52                         *ex = u.bits.exp - 0x4200;
  53                         u.bits.exp = 0x3ffe;
  54                 }
  55                 break;
  56         case 0x7fff:    /* infinity or NaN; value of *ex is unspecified */
  57                 break;
  58         default:        /* normal */
  59                 *ex = u.bits.exp - 0x3ffe;
  60                 u.bits.exp = 0x3ffe;
  61                 break;
  62         }
  63         return (u.e);
  64 }