1//===-- floatundixf.c - Implement __floatundixf ---------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements __floatundixf for the compiler_rt library.
10//
11//===----------------------------------------------------------------------===//
12
13#if !_ARCH_PPC
14
15#include "int_lib.h"
16
17// Returns: convert a to a long double, rounding toward even.
18
19// Assumption: long double is a IEEE 80 bit floating point type padded to 128
20// bits du_int is a 64 bit integral type
21
22// gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee
23// eeee | 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm
24// mmmm mmmm mmmm
25COMPILER_RT_ABI xf_float __floatundixf(du_int a) {
26 if (a == 0)
27 return 0.0;
28 const unsigned N = sizeof(du_int) * CHAR_BIT;
29 int clz = __builtin_clzll(a);
30 int e = (N - 1) - clz; // exponent
31 xf_bits fb;
32 fb.u.high.s.low = (e + 16383); // exponent
33 fb.u.low.all = a << clz; // mantissa
34 return fb.f;
35}
36
37#endif // _ARCH_PPC
38

source code of compiler-rt/lib/builtins/floatundixf.c