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 #if defined(ELFOBJ)
  31 #pragma weak truncl = __truncl
  32 #endif
  33 
  34 #include "libm.h"
  35 
  36 #if defined(__sparc)
  37 long double
  38 truncl(long double x) {
  39         union {
  40                 unsigned i[4];
  41                 long double q;
  42         } xx;
  43         unsigned hx, sx;
  44         int j;
  45 
  46         xx.q = x;
  47         sx = xx.i[0] & 0x80000000;
  48         hx = xx.i[0] & ~0x80000000;
  49 
  50         /* handle trivial cases */
  51         if (hx >= 0x406f0000) /* |x| >= 2^112 + ... or x is nan */
  52                 return (hx >= 0x7fff0000 ? x + x : x);
  53 
  54         /* handle |x| < 1 */
  55         if (hx < 0x3fff0000)
  56                 return (sx ? -0.0L : 0.0L);
  57 
  58         j = 0x406f - (hx >> 16);          /* 1 <= j <= 112 */
  59         xx.i[0] = hx;
  60         if (j >= 96) {                               /* 96 <= j <= 112 */
  61                 xx.i[0] &= ~((1 << (j - 96)) - 1);
  62                 xx.i[1] = xx.i[2] = xx.i[3] = 0;
  63         } else if (j >= 64) {                        /* 64 <= j <= 95 */
  64                 xx.i[1] &= ~((1 << (j - 64)) - 1);
  65                 xx.i[2] = xx.i[3] = 0;
  66         } else if (j >= 32) {                        /* 32 <= j <= 63 */
  67                 xx.i[2] &= ~((1 << (j - 32)) - 1);
  68                 xx.i[3] = 0;
  69         } else                                  /* 1 <= j <= 31 */
  70                 xx.i[3] &= ~((1 << j) - 1);
  71 
  72         /* negate result if need be */
  73         if (sx)
  74                 xx.i[0] |= 0x80000000;
  75         return (xx.q);
  76 }
  77 #elif defined(__x86)
  78 long double
  79 truncl(long double x) {
  80         union {
  81                 unsigned i[3];
  82                 long double e;
  83         } xx;
  84         int ex, sx, i;
  85 
  86         xx.e = x;
  87         ex = xx.i[2] & 0x7fff;
  88         sx = xx.i[2] & 0x8000;
  89         if (ex < 0x403e) {   /* |x| < 2^63 */
  90                 if (ex < 0x3fff)     /* |x| < 1 */
  91                         return (sx ? -0.0L : 0.0L);
  92 
  93                 /* chop x at the integer bit */
  94                 if (ex < 0x401e) {
  95                         i = 1 << (0x401d - ex);
  96                         xx.i[1] &= ~(i | (i - 1));
  97                         xx.i[0] = 0;
  98                 } else {
  99                         i = 1 << (0x403d - ex);
 100                         xx.i[0] &= ~(i | (i - 1));
 101                 }
 102                 return (xx.e);
 103         } else if (ex < 0x7fff)      /* x is integral */
 104                 return (x);
 105         else                    /* inf or nan */
 106                 return (x + x);
 107 }
 108 #else
 109 #error Unknown architecture
 110 #endif  /* defined(__sparc) || defined(__x86) */