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 __llroundl = llroundl
  31 #if defined(__sparcv9) || defined(__amd64)
  32 #pragma weak lroundl = llroundl
  33 #pragma weak __lroundl = llroundl
  34 #endif
  35 
  36 #include "libm.h"
  37 
  38 #if defined(__sparc)
  39 long long
  40 llroundl(long double x) {
  41         union {
  42                 unsigned i[4];
  43                 long double q;
  44         } xx;
  45         union {
  46                 unsigned i[2];
  47                 long long l;
  48         } zz;
  49         union {
  50                 unsigned i;
  51                 float f;
  52         } tt;
  53         unsigned hx, sx, frac;
  54         int j;
  55 
  56         xx.q = x;
  57         sx = xx.i[0] & 0x80000000;
  58         hx = xx.i[0] & ~0x80000000;
  59 
  60         /* handle trivial cases */
  61         if (hx > 0x403e0000) { /* |x| > 2^63 + ... or x is nan */
  62                 /* convert an out-of-range float */
  63                 tt.i = sx | 0x7f000000;
  64                 return ((long long) tt.f);
  65         }
  66 
  67         /* handle |x| < 1 */
  68         if (hx < 0x3fff0000) {
  69                 if (hx >= 0x3ffe0000)
  70                         return (sx ? -1LL : 1LL);
  71                 return (0LL);
  72         }
  73 
  74         /* extract the integer and fractional parts of x */
  75         j = 0x406f - (hx >> 16);
  76         xx.i[0] = 0x10000 | (xx.i[0] & 0xffff);
  77         if (j >= 96) {
  78                 zz.i[0] = 0;
  79                 zz.i[1] = xx.i[0] >> (j - 96);
  80                 frac = ((xx.i[0] << 1) << (127 - j)) | (xx.i[1] >> (j - 96));
  81                 if (((xx.i[1] << 1) << (127 - j)) | xx.i[2] | xx.i[3])
  82                         frac |= 1;
  83         } else if (j >= 64) {
  84                 zz.i[0] = xx.i[0] >> (j - 64);
  85                 zz.i[1] = ((xx.i[0] << 1) << (95 - j)) | (xx.i[1] >> (j - 64));
  86                 frac = ((xx.i[1] << 1) << (95 - j)) | (xx.i[2] >> (j - 64));
  87                 if (((xx.i[2] << 1) << (95 - j)) | xx.i[3])
  88                         frac |= 1;
  89         } else {
  90                 zz.i[0] = ((xx.i[0] << 1) << (63 - j)) | (xx.i[1] >> (j - 32));
  91                 zz.i[1] = ((xx.i[1] << 1) << (63 - j)) | (xx.i[2] >> (j - 32));
  92                 frac = ((xx.i[2] << 1) << (63 - j)) | (xx.i[3] >> (j - 32));
  93                 if ((xx.i[3] << 1) << (63 - j))
  94                         frac |= 1;
  95         }
  96 
  97         /* round */
  98         if (frac >= 0x80000000u) {
  99                 if (++zz.i[1] == 0)
 100                         zz.i[0]++;
 101         }
 102 
 103         /* check for result out of range (note that z is |x| at this point) */
 104         if (zz.i[0] > 0x80000000u || (zz.i[0] == 0x80000000 && (zz.i[1] ||
 105                 !sx))) {
 106                 tt.i = sx | 0x7f000000;
 107                 return ((long long) tt.f);
 108         }
 109 
 110         /* negate result if need be */
 111         if (sx) {
 112                 zz.i[0] = ~zz.i[0];
 113                 zz.i[1] = -zz.i[1];
 114                 if (zz.i[1] == 0)
 115                         zz.i[0]++;
 116         }
 117 
 118         return (zz.l);
 119 }
 120 #elif defined(__x86)
 121 long long
 122 llroundl(long double x) {
 123         union {
 124                 unsigned i[3];
 125                 long double e;
 126         } xx;
 127         int ex, sx, i;
 128 
 129         xx.e = x;
 130         ex = xx.i[2] & 0x7fff;
 131         sx = xx.i[2] & 0x8000;
 132 
 133         if (ex < 0x403e) { /* |x| < 2^63 */
 134                 /* handle |x| < 1 */
 135                 if (ex < 0x3fff) {
 136                         if (ex >= 0x3ffe)
 137                                 return (sx ? -1LL : 1LL);
 138                         return (0LL);
 139                 }
 140 
 141                 /* round x at the integer bit */
 142                 if (ex < 0x401e) {
 143                         i = 1 << (0x401d - ex);
 144                         xx.i[1] = (xx.i[1] + i) & ~(i | (i - 1));
 145                         xx.i[0] = 0;
 146                 } else {
 147                         i = 1 << (0x403d - ex);
 148                         xx.i[0] += i;
 149                         if (xx.i[0] < i)
 150                                 xx.i[1]++;
 151                         xx.i[0] &= ~(i | (i - 1));
 152                 }
 153                 if (xx.i[1] == 0) {
 154                         xx.i[2] = sx | ++ex;
 155                         xx.i[1] = 0x80000000U;
 156                 }
 157         }
 158 
 159         /* now x is nan, inf, or integral */
 160         return ((long long) xx.e);
 161 }
 162 #else
 163 #error Unknown architecture
 164 #endif