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