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 modfl = __modfl
  32 #endif
  33 
  34 #include "libm.h"
  35 
  36 #if defined(__sparc)
  37 
  38 long double
  39 __modfl(long double x, long double *iptr) {
  40         union {
  41                 unsigned i[4];
  42                 long double q;
  43         } xx, yy;
  44         unsigned hx, s;
  45 
  46         xx.q = x;
  47         hx = xx.i[0] & ~0x80000000;
  48 
  49         if (hx >= 0x406f0000) {      /* x is NaN, infinite, or integral */
  50                 *iptr = x;
  51                 if (hx < 0x7fff0000 || (hx == 0x7fff0000 &&
  52                         (xx.i[1] | xx.i[2] | xx.i[3]) == 0)) {
  53                         xx.i[0] &= 0x80000000;
  54                         xx.i[1] = xx.i[2] = xx.i[3] = 0;
  55                 }
  56                 return (xx.q);
  57         }
  58 
  59         if (hx < 0x3fff0000) {       /* |x| < 1 */
  60                 xx.i[0] &= 0x80000000;
  61                 xx.i[1] = xx.i[2] = xx.i[3] = 0;
  62                 *iptr = xx.q;
  63                 return (x);
  64         }
  65 
  66         /* split x at the binary point */
  67         s = xx.i[0] & 0x80000000;
  68         if (hx < 0x40100000) {
  69                 yy.i[0] = xx.i[0] & ~((1 << (0x400f - (hx >> 16))) - 1);
  70                 yy.i[1] = yy.i[2] = yy.i[3] = 0;
  71         } else if (hx < 0x40300000) {
  72                 yy.i[0] = xx.i[0];
  73                 yy.i[1] = xx.i[1] & ~((1 << (0x402f - (hx >> 16))) - 1);
  74                 yy.i[2] = yy.i[3] = 0;
  75         } else if (hx < 0x40500000) {
  76                 yy.i[0] = xx.i[0];
  77                 yy.i[1] = xx.i[1];
  78                 yy.i[2] = xx.i[2] & ~((1 << (0x404f - (hx >> 16))) - 1);
  79                 yy.i[3] = 0;
  80         } else {
  81                 yy.i[0] = xx.i[0];
  82                 yy.i[1] = xx.i[1];
  83                 yy.i[2] = xx.i[2];
  84                 yy.i[3] = xx.i[3] & ~((1 << (0x406f - (hx >> 16))) - 1);
  85         }
  86         *iptr = yy.q;
  87 
  88         /*
  89          * we could implement the following more efficiently than by using
  90          * software emulation of fsubq, but we'll do it this way for now
  91          * (and hope hardware support becomes commonplace)
  92          */
  93         xx.q -= yy.q;
  94         xx.i[0] = (xx.i[0] & ~0x80000000) | s;      /* keep sign of x */
  95         return (xx.q);
  96 }
  97 
  98 #elif defined(__x86)
  99 
 100 long double
 101 __modfl(long double x, long double *iptr) {
 102         union {
 103                 unsigned i[3];
 104                 long double e;
 105         } xx, yy;
 106         unsigned hx, s;
 107 
 108         /*
 109          * It might be faster to use one of the x86 fpops instead of
 110          * the following.
 111          */
 112         xx.e = x;
 113         hx = xx.i[2] & 0x7fff;
 114 
 115         if (hx >= 0x403e) {  /* x is NaN, infinite, or integral */
 116                 *iptr = x;
 117                 if (hx < 0x7fff || (hx == 0x7fff &&
 118                         ((xx.i[1] << 1) | xx.i[0]) == 0)) {
 119                         xx.i[2] &= 0x8000;
 120                         xx.i[1] = xx.i[0] = 0;
 121                 }
 122                 return (xx.e);
 123         }
 124 
 125         if (hx < 0x3fff) {   /* |x| < 1 */
 126                 xx.i[2] &= 0x8000;
 127                 xx.i[1] = xx.i[0] = 0;
 128                 *iptr = xx.e;
 129                 return (x);
 130         }
 131 
 132         /* split x at the binary point */
 133         s = xx.i[2] & 0x8000;
 134         yy.i[2] = xx.i[2];
 135         if (hx < 0x401f) {
 136                 yy.i[1] = xx.i[1] & ~((1 << (0x401e - hx)) - 1);
 137                 yy.i[0] = 0;
 138         } else {
 139                 yy.i[1] = xx.i[1];
 140                 yy.i[0] = xx.i[0] & ~((1 << (0x403e - hx)) - 1);
 141         }
 142         *iptr = yy.e;
 143         xx.e -= yy.e;
 144         xx.i[2] = (xx.i[2] & ~0x8000) | s;  /* keep sign of x */
 145         return (xx.e);
 146 }
 147 
 148 #else
 149 #error Unknown architecture
 150 #endif