Blame view

RIOT/sys/quad_math/fixunsdfdi.c 2.94 KB
a752c7ab   elopes   add first test an...
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
  /* $OpenBSD: fixunsdfdi.c,v 1.7 2005/08/08 08:05:35 espie Exp $ */
  /*-
   * Copyright (c) 1992, 1993
   * The Regents of the University of California.  All rights reserved.
   *
   * This software was developed by the Computer Systems Engineering group
   * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
   * contributed to Berkeley.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Neither the name of the University nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  
  #include "quad.h"
  
  #define ONE_FOURTH  ((int) 1 << (INT_BITS - 2))
  #define ONE_HALF    (ONE_FOURTH * 2.0)
  #define ONE     (ONE_FOURTH * 4.0)
  
  /*
   * Convert double to (unsigned) quad.
   * Not sure what to do with negative numbers---for now, anything out
   * of range becomes UQUAD_MAX.
   */
  u_quad_t __fixunsdfdi(double x)
  {
      union uu t;
      unsigned int tmp;
  
      if (x < 0) {
          return (UQUAD_MAX); /* ??? should be 0?  ERANGE??? */
      }
  
  #ifdef notdef               /* this falls afoul of a GCC bug */
      if (x >= UQUAD_MAX) {
          return (UQUAD_MAX);
      }
  #else                   /* so we wire in 2^64-1 instead */
      if (x >= 18446744073709551615.0) {   /* XXX */
          return (UQUAD_MAX);
      }
  #endif
  
      /*
       * Now we know that 0 <= x <= 18446744073709549568.  The upper
       * limit is one ulp less than 18446744073709551615 tested for above.
       * Dividing this by 2^32 will *not* round irrespective of any
       * rounding modes (except if the result is an IEEE denorm).
       * Furthermore, the quotient will fit into a 32-bit integer.
       */
      tmp = x / ONE;
      t.ul[L] = (unsigned int) (x - tmp * ONE);
      t.ul[H] = tmp;
      return (t.uq);
  }