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 __lroundl = lroundl
  32 
  33 #include <sys/isa_defs.h>         /* _ILP32 */
  34 #include "libm.h"
  35 
  36 #if defined(_ILP32)
  37 #if defined(__sparc)
  38 long
  39 lroundl(long double x)
  40 {
  41         union {
  42                 unsigned i[4];
  43                 long double q;
  44         } xx;
  45         union {
  46                 unsigned i;
  47                 float f;
  48         } tt;
  49 
  50         unsigned hx, sx, frac, l;
  51         int j;
  52 
  53         xx.q = x;
  54         sx = xx.i[0] & 0x80000000;
  55         hx = xx.i[0] & ~0x80000000;
  56 
  57         /* handle trivial cases */
  58         if (hx > 0x401e0000) {               /* |x| > 2^31 + ... or x is nan */
  59                 /* convert an out-of-range float */
  60                 tt.i = sx | 0x7f000000;
  61                 return ((long)tt.f);
  62         }
  63 
  64         /* handle |x| < 1 */
  65         if (hx < 0x3fff0000) {
  66                 if (hx >= 0x3ffe0000)
  67                         return (sx ? -1L : 1L);
  68 
  69                 return (0L);
  70         }
  71 
  72         /* extract the integer and fractional parts of x */
  73         j = 0x406f - (hx >> 16);  /* 91 <= j <= 112 */
  74         xx.i[0] = 0x10000 | (xx.i[0] & 0xffff);
  75 
  76         if (j >= 96) {                       /* 96 <= j <= 112 */
  77                 l = xx.i[0] >> (j - 96);
  78                 frac = ((xx.i[0] << 1) << (127 - j)) | (xx.i[1] >> (j - 96));
  79 
  80                 if (((xx.i[1] << 1) << (127 - j)) | xx.i[2] | xx.i[3])
  81                         frac |= 1;
  82         } else {                        /* 91 <= j <= 95 */
  83                 l = (xx.i[0] << (96 - j)) | (xx.i[1] >> (j - 64));
  84                 frac = (xx.i[1] << (96 - j)) | (xx.i[2] >> (j - 64));
  85 
  86                 if ((xx.i[2] << (96 - j)) | xx.i[3])
  87                         frac |= 1;
  88         }
  89 
  90         /* round */
  91         if (frac >= 0x80000000U)
  92                 l++;
  93 
  94         /* check for result out of range (note that z is |x| at this point) */
  95         if (l > 0x80000000U || (l == 0x80000000U && !sx)) {
  96                 tt.i = sx | 0x7f000000;
  97                 return ((long)tt.f);
  98         }
  99 
 100         /* negate result if need be */
 101         if (sx)
 102                 l = -l;
 103 
 104         return ((long)l);
 105 }
 106 #elif defined(__x86)
 107 long
 108 lroundl(long double x)
 109 {
 110         union {
 111                 unsigned i[3];
 112                 long double e;
 113         } xx;
 114 
 115         int ex, sx, i;
 116 
 117         xx.e = x;
 118         ex = xx.i[2] & 0x7fff;
 119         sx = xx.i[2] & 0x8000;
 120 
 121         if (ex < 0x403e) {           /* |x| < 2^63 */
 122                 if (ex < 0x3fff) {   /* |x| < 1 */
 123                         if (ex >= 0x3ffe)
 124                                 return (sx ? -1L : 1L);
 125 
 126                         return (0L);
 127                 }
 128 
 129                 /* round x at the integer bit */
 130                 if (ex < 0x401e) {
 131                         i = 1 << (0x401d - ex);
 132                         xx.i[1] = (xx.i[1] + i) & ~(i | (i - 1));
 133                         xx.i[0] = 0;
 134                 } else {
 135                         i = 1 << (0x403d - ex);
 136                         xx.i[0] += i;
 137 
 138                         if (xx.i[0] < i)
 139                                 xx.i[1]++;
 140 
 141                         xx.i[0] &= ~(i | (i - 1));
 142                 }
 143 
 144                 if (xx.i[1] == 0) {
 145                         xx.i[2] = sx | ++ex;
 146                         xx.i[1] = 0x80000000U;
 147                 }
 148         }
 149 
 150         /* now x is nan, inf, or integral */
 151         return ((long)xx.e);
 152 }
 153 #else
 154 #error Unknown architecture
 155 #endif /* defined(__sparc) || defined(__x86) */
 156 #else
 157 #error Unsupported architecture
 158 #endif /* defined(_ILP32) */