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 /*
  27  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  28  * Use is subject to license terms.
  29  */
  30 
  31 #pragma weak __truncl = truncl
  32 
  33 #include "libm.h"
  34 
  35 #if defined(__sparc)
  36 long double
  37 truncl(long double x)
  38 {
  39         union {
  40                 unsigned i[4];
  41                 long double q;
  42         } xx;
  43 
  44         unsigned hx, sx;
  45         int j;
  46 
  47         xx.q = x;
  48         sx = xx.i[0] & 0x80000000;
  49         hx = xx.i[0] & ~0x80000000;
  50 
  51         /* handle trivial cases */
  52         if (hx >= 0x406f0000)                /* |x| >= 2^112 + ... or x is nan */
  53                 return (hx >= 0x7fff0000 ? x + x : x);
  54 
  55         /* handle |x| < 1 */
  56         if (hx < 0x3fff0000)
  57                 return (sx ? -0.0L : 0.0L);
  58 
  59         j = 0x406f - (hx >> 16);  /* 1 <= j <= 112 */
  60         xx.i[0] = hx;
  61 
  62         if (j >= 96) {                       /* 96 <= j <= 112 */
  63                 xx.i[0] &= ~((1 << (j - 96)) - 1);
  64                 xx.i[1] = xx.i[2] = xx.i[3] = 0;
  65         } else if (j >= 64) {                /* 64 <= j <= 95 */
  66                 xx.i[1] &= ~((1 << (j - 64)) - 1);
  67                 xx.i[2] = xx.i[3] = 0;
  68         } else if (j >= 32) {                /* 32 <= j <= 63 */
  69                 xx.i[2] &= ~((1 << (j - 32)) - 1);
  70                 xx.i[3] = 0;
  71         } else {                        /* 1 <= j <= 31 */
  72                 xx.i[3] &= ~((1 << j) - 1);
  73         }
  74 
  75         /* negate result if need be */
  76         if (sx)
  77                 xx.i[0] |= 0x80000000;
  78 
  79         return (xx.q);
  80 }
  81 #elif defined(__x86)
  82 long double
  83 truncl(long double x)
  84 {
  85         union {
  86                 unsigned i[3];
  87                 long double e;
  88         } xx;
  89 
  90         int ex, sx, i;
  91 
  92         xx.e = x;
  93         ex = xx.i[2] & 0x7fff;
  94         sx = xx.i[2] & 0x8000;
  95 
  96         if (ex < 0x403e) {           /* |x| < 2^63 */
  97                 if (ex < 0x3fff)     /* |x| < 1 */
  98                         return (sx ? -0.0L : 0.0L);
  99 
 100                 /* chop x at the integer bit */
 101                 if (ex < 0x401e) {
 102                         i = 1 << (0x401d - ex);
 103                         xx.i[1] &= ~(i | (i - 1));
 104                         xx.i[0] = 0;
 105                 } else {
 106                         i = 1 << (0x403d - ex);
 107                         xx.i[0] &= ~(i | (i - 1));
 108                 }
 109 
 110                 return (xx.e);
 111         } else if (ex < 0x7fff) {    /* x is integral */
 112                 return (x);
 113         } else {                        /* inf or nan */
 114                 return (x + x);
 115         }
 116 }
 117 #else
 118 #error Unknown architecture
 119 #endif /* defined(__sparc) || defined(__x86) */