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
|
/*****************************************************************
*
* The Compcert verified compiler
*
* Xavier Leroy, INRIA Paris-Rocquencourt
*
* Copyright (c) 2013 Institut National de Recherche en Informatique et
* en Automatique.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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.
* * Neither the name of the <organization> 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 COPYRIGHT HOLDERS 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 <COPYRIGHT
* HOLDER> 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.
*
**********************************************************************/
/* Helper functions for 64-bit integer arithmetic. Reference C implementation */
#include "i64.h"
/* Conversion from signed int64 to float32 */
float i64_stof(signed long long x)
{
if (x < -(1LL << 53) || x >= (1LL << 53)) {
/* x is large enough that double rounding can occur.
Nudge x away from the points where double rounding occurs
(the "round to odd" technique) */
unsigned delta = ((unsigned) x & 0x7FF) + 0x7FF;
x = (x | delta) & ~0x7FFLL;
}
/* Convert to double */
unsigned xl = x;
signed xh = x >> 32;
double r = (double) xl + 0x1.0p32 * (double) xh;
/* Round to single */
return (float) r;
}
|
