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1 | /* ===-- floatundixf.c - Implement __floatundixf ---------------------------=== |
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 __floatundixf for the compiler_rt library. | |
11 | * | |
12 | * ===----------------------------------------------------------------------=== | |
13 | */ | |
14 | ||
15 | #if !_ARCH_PPC | |
16 | ||
17 | #include "int_lib.h" | |
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 | * du_int is a 64 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 | COMPILER_RT_ABI long double | |
29 | __floatundixf(du_int a) | |
30 | { | |
31 | if (a == 0) | |
32 | return 0.0; | |
33 | const unsigned N = sizeof(du_int) * CHAR_BIT; | |
34 | int clz = __builtin_clzll(a); | |
35 | int e = (N - 1) - clz ; /* exponent */ | |
36 | long_double_bits fb; | |
37 | fb.u.high.s.low = (e + 16383); /* exponent */ | |
38 | fb.u.low.all = a << clz; /* mantissa */ | |
39 | return fb.f; | |
40 | } | |
41 | ||
42 | #endif /* _ARCH_PPC */ |