1//===-- fixunsxfti.c - Implement __fixunsxfti -----------------------------===//
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 __fixunsxfti for the compiler_rt library.
10//
11//===----------------------------------------------------------------------===//
12
13#include "int_lib.h"
14
15#ifdef CRT_HAS_128BIT
16
17// Returns: convert a to a unsigned long long, rounding toward zero.
18//          Negative values all become zero.
19
20// Assumption: long double is an intel 80 bit floating point type padded with 6
21// bytes tu_int is a 128 bit integral type value in long double is representable
22// in tu_int or is negative
23
24// gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee
25// eeee | 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm
26// mmmm mmmm mmmm
27
28COMPILER_RT_ABI tu_int __fixunsxfti(long double a) {
29  long_double_bits fb;
30  fb.f = a;
31  int e = (fb.u.high.s.low & 0x00007FFF) - 16383;
32  if (e < 0 || (fb.u.high.s.low & 0x00008000))
33    return 0;
34  if ((unsigned)e > sizeof(tu_int) * CHAR_BIT)
35    return ~(tu_int)0;
36  tu_int r = fb.u.low.all;
37  if (e > 63)
38    r <<= (e - 63);
39  else
40    r >>= (63 - e);
41  return r;
42}
43
44#endif // CRT_HAS_128BIT
45