OpenCores
URL https://opencores.org/ocsvn/openrisc_me/openrisc_me/trunk

Subversion Repositories openrisc_me

[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.17.0/] [newlib/] [libm/] [common/] [s_round.c] - Blame information for rev 455

Go to most recent revision | Details | Compare with Previous | View Log

Line No. Rev Author Line
1 148 jeremybenn 
/*
2 
 * ====================================================
3 
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
4 
 *
5 
 * Developed at SunPro, a Sun Microsystems, Inc. business.
6 
 * Permission to use, copy, modify, and distribute this
7 
 * software is freely granted, provided that this notice
8 
 * is preserved.
9 
 * ====================================================
10 
 */
11 
 
12 
#include "fdlibm.h"
13 
 
14 
#ifndef _DOUBLE_IS_32BITS
15 
 
16 
#ifdef __STDC__
17 
        double round(double x)
18 
#else
19 
        double round(x)
20 
        double x;
21 
#endif
22 
{
23 
  /* Most significant word, least significant word. */
24 
  __int32_t msw, exponent_less_1023;
25 
  __uint32_t lsw;
26 
 
27 
  EXTRACT_WORDS(msw, lsw, x);
28 
 
29 
  /* Extract exponent field. */
30 
  exponent_less_1023 = ((msw & 0x7ff00000) >> 20) - 1023;
31 
 
32 
  if (exponent_less_1023 < 20)
33 
    {
34 
      if (exponent_less_1023 < 0)
35 
        {
36 
          msw &= 0x80000000;
37 
          if (exponent_less_1023 == -1)
38 
            /* Result is +1.0 or -1.0. */
39 
            msw |= (1023 << 20);
40 
          lsw = 0;
41 
        }
42 
      else
43 
        {
44 
          __uint32_t exponent_mask = 0x000fffff >> exponent_less_1023;
45 
          if ((msw & exponent_mask) == 0 && lsw == 0)
46 
            /* x in an integral value. */
47 
            return x;
48 
 
49 
          msw += 0x00080000 >> exponent_less_1023;
50 
          msw &= ~exponent_mask;
51 
          lsw = 0;
52 
        }
53 
    }
54 
  else if (exponent_less_1023 > 51)
55 
    {
56 
      if (exponent_less_1023 == 1024)
57 
        /* x is NaN or infinite. */
58 
        return x + x;
59 
      else
60 
        return x;
61 
    }
62 
  else
63 
    {
64 
      __uint32_t exponent_mask = 0xffffffff >> (exponent_less_1023 - 20);
65 
      __uint32_t tmp;
66 
 
67 
      if ((lsw & exponent_mask) == 0)
68 
        /* x is an integral value. */
69 
        return x;
70 
 
71 
      tmp = lsw + (1 << (51 - exponent_less_1023));
72 
      if (tmp < lsw)
73 
        msw += 1;
74 
      lsw = tmp;
75 
 
76 
      lsw &= ~exponent_mask;
77 
    }
78 
  INSERT_WORDS(x, msw, lsw);
79 
 
80 
  return x;
81 
}
82 
 
83 
#endif /* _DOUBLE_IS_32BITS */

powered by: WebSVN 2.1.0

© copyright 1999-2024 OpenCores.org, equivalent to Oliscience, all rights reserved. OpenCores®, registered trademark.