GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libcompiler_rt/muloti4.c Lines: 0 22 0.0 %
Date: 2017-11-13 Branches: 0 16 0.0 %

Line Branch Exec Source
1
/*===-- muloti4.c - Implement __muloti4 -----------------------------------===
2
 *
3
 *                     The LLVM Compiler Infrastructure
4
 *
5
 * This file is dual licensed under the MIT and the University of Illinois Open
6
 * Source Licenses. See LICENSE.TXT for details.
7
 *
8
 * ===----------------------------------------------------------------------===
9
 *
10
 * This file implements __muloti4 for the compiler_rt library.
11
 *
12
 * ===----------------------------------------------------------------------===
13
 */
14
15
#include "int_lib.h"
16
17
#ifdef CRT_HAS_128BIT
18
19
/* Returns: a * b */
20
21
/* Effects: sets *overflow to 1  if a * b overflows */
22
23
COMPILER_RT_ABI ti_int
24
__muloti4(ti_int a, ti_int b, int* overflow)
25
{
26
    const int N = (int)(sizeof(ti_int) * CHAR_BIT);
27
    const ti_int MIN = (ti_int)1 << (N-1);
28
    const ti_int MAX = ~MIN;
29
    *overflow = 0;
30
    ti_int result = a * b;
31
    if (a == MIN)
32
    {
33
        if (b != 0 && b != 1)
34
	    *overflow = 1;
35
	return result;
36
    }
37
    if (b == MIN)
38
    {
39
        if (a != 0 && a != 1)
40
	    *overflow = 1;
41
        return result;
42
    }
43
    ti_int sa = a >> (N - 1);
44
    ti_int abs_a = (a ^ sa) - sa;
45
    ti_int sb = b >> (N - 1);
46
    ti_int abs_b = (b ^ sb) - sb;
47
    if (abs_a < 2 || abs_b < 2)
48
        return result;
49
    if (sa == sb)
50
    {
51
        if (abs_a > MAX / abs_b)
52
            *overflow = 1;
53
    }
54
    else
55
    {
56
        if (abs_a > MIN / -abs_b)
57
            *overflow = 1;
58
    }
59
    return result;
60
}
61
62
#endif /* CRT_HAS_128BIT */