GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libcompiler_rt/floatuntixf.c Lines: 0 20 0.0 %
Date: 2017-11-13 Branches: 0 9 0.0 %

Line Branch Exec Source
1
/* ===-- floatuntixf.c - Implement __floatuntixf ---------------------------===
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 __floatuntixf for the compiler_rt library.
11
 *
12
 * ===----------------------------------------------------------------------===
13
 */
14
15
#include "int_lib.h"
16
17
#ifdef CRT_HAS_128BIT
18
19
/* Returns: convert a to a long double, rounding toward even. */
20
21
/* Assumption: long double is a IEEE 80 bit floating point type padded to 128 bits
22
 *             tu_int is a 128 bit integral type
23
 */
24
25
/* gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee eeee |
26
 * 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm
27
 */
28
29
COMPILER_RT_ABI long double
30
__floatuntixf(tu_int a)
31
{
32
    if (a == 0)
33
        return 0.0;
34
    const unsigned N = sizeof(tu_int) * CHAR_BIT;
35
    int sd = N - __clzti2(a);  /* number of significant digits */
36
    int e = sd - 1;             /* exponent */
37
    if (sd > LDBL_MANT_DIG)
38
    {
39
        /*  start:  0000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQxxxxxxxxxxxxxxxxxx
40
         *  finish: 000000000000000000000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQR
41
         *                                                12345678901234567890123456
42
         *  1 = msb 1 bit
43
         *  P = bit LDBL_MANT_DIG-1 bits to the right of 1
44
         *  Q = bit LDBL_MANT_DIG bits to the right of 1
45
         *  R = "or" of all bits to the right of Q
46
	 */
47
        switch (sd)
48
        {
49
        case LDBL_MANT_DIG + 1:
50
            a <<= 1;
51
            break;
52
        case LDBL_MANT_DIG + 2:
53
            break;
54
        default:
55
            a = (a >> (sd - (LDBL_MANT_DIG+2))) |
56
                ((a & ((tu_int)(-1) >> ((N + LDBL_MANT_DIG+2) - sd))) != 0);
57
        };
58
        /* finish: */
59
        a |= (a & 4) != 0;  /* Or P into R */
60
        ++a;  /* round - this step may add a significant bit */
61
        a >>= 2;  /* dump Q and R */
62
        /* a is now rounded to LDBL_MANT_DIG or LDBL_MANT_DIG+1 bits */
63
        if (a & ((tu_int)1 << LDBL_MANT_DIG))
64
        {
65
            a >>= 1;
66
            ++e;
67
        }
68
        /* a is now rounded to LDBL_MANT_DIG bits */
69
    }
70
    else
71
    {
72
        a <<= (LDBL_MANT_DIG - sd);
73
        /* a is now rounded to LDBL_MANT_DIG bits */
74
    }
75
    long_double_bits fb;
76
    fb.u.high.s.low = (e + 16383);                  /* exponent */
77
    fb.u.low.all = (du_int)a;                     /* mantissa */
78
    return fb.f;
79
}
80
81
#endif