usr/src/lib/libm/common/m9x/frexpl.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  24  */
  25 /*
  26  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  27  * Use is subject to license terms.
  28  */
  29
  30 #pragma weak frexpl = __frexpl
  31
  32 #include "libm.h"
  33
  34 #if defined(__sparc)
  35
  36 long double
  37 __frexpl(long double x, int *exp) {
  38         union {
  39                 unsigned i[4];
  40                 long double q;
  41         } xx;
  42         unsigned hx;
  43         int e, s;
  44
  45         xx.q = x;
  46         hx = xx.i[0] & ~0x80000000;
  47
  48         if (hx >= 0x7fff0000) { /* x is infinite or NaN */
  49                 *exp = 0;
  50                 return (x);
  51         }
  52
  53         e = 0;
  54         if (hx < 0x00010000) {  /* x is subnormal or zero */
  55                 if ((hx | xx.i[1] | xx.i[2] | xx.i[3]) == 0) {
  56                         *exp = 0;
  57                         return (x);
  58                 }
  59
  60                 /* normalize x */
  61                 s = xx.i[0] & 0x80000000;
  62                 while ((hx | (xx.i[1] & 0xffff0000)) == 0) {
  63                         hx = xx.i[1];
  64                         xx.i[1] = xx.i[2];
  65                         xx.i[2] = xx.i[3];
  66                         xx.i[3] = 0;
  67                         e -= 32;
  68                 }
  69                 while (hx < 0x10000) {
  70                         hx = (hx << 1) | (xx.i[1] >> 31);
  71                         xx.i[1] = (xx.i[1] << 1) | (xx.i[2] >> 31);
  72                         xx.i[2] = (xx.i[2] << 1) | (xx.i[3] >> 31);
  73                         xx.i[3] <<= 1;
  74                         e--;
  75                 }
  76                 xx.i[0] = s | hx;
  77         }
  78
  79         /* now xx.q is normal */
  80         xx.i[0] = (xx.i[0] & ~0x7fff0000) | 0x3ffe0000;
  81         *exp = e + (hx >> 16) - 0x3ffe;
  82         return (xx.q);
  83 }
  84
  85 #elif defined(__x86)
  86
  87 long double
  88 __frexpl(long double x, int *exp) {
  89         union {
  90                 unsigned i[3];
  91                 long double e;
  92         } xx;
  93         unsigned hx;
  94         int e;
  95
  96         xx.e = x;
  97         hx = xx.i[2] & 0x7fff;
  98
  99         if (hx >= 0x7fff) {     /* x is infinite or NaN */
 100                 *exp = 0;
 101                 return (x);
 102         }
 103
 104         e = 0;
 105         if (hx < 0x0001) {      /* x is subnormal or zero */
 106                 if ((xx.i[0] | xx.i[1]) == 0) {
 107                         *exp = 0;
 108                         return (x);
 109                 }
 110
 111                 /* normalize x */
 112                 xx.e *= 18446744073709551616.0L;        /* 2^64 */
 113                 hx = xx.i[2] & 0x7fff;
 114                 e = -64;
 115         }
 116
 117         /* now xx.e is normal */
 118         xx.i[2] = (xx.i[2] & 0x8000) | 0x3ffe;
 119         *exp = e + hx - 0x3ffe;
 120         return (xx.e);
 121 }
 122
 123 #else
 124 #error Unknown architecture
 125 #endif