fixtfti.c revision 360784 
1//===--- lib/builtins/ppc/fixtfti.c - Convert long double->int128 *-C -*---===//
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 converting the 128bit IBM/PowerPC long double (double-
10// double) data type to a signed 128 bit integer.
11//
12//===----------------------------------------------------------------------===//
13
14#include "../int_math.h"
15
16// Convert long double into a signed 128-bit integer.
17__int128_t __fixtfti(long double input) {
18
19  // If we are trying to convert a NaN, return the NaN bit pattern.
20  if (crt_isnan(input)) {
21    return ((__uint128_t)0x7FF8000000000000ll) << 64 |
22           (__uint128_t)0x0000000000000000ll;
23  }
24
25  // Note: overflow is an undefined behavior for this conversion.
26  // For this reason, overflow is not checked here.
27
28  // If the long double is negative, use unsigned conversion from its absolute
29  // value.
30  if (input < 0.0) {
31    __uint128_t result = (__uint128_t)(-input);
32    return -((__int128_t)result);
33  }
34
35  // Otherwise, use unsigned conversion from the input value.
36  __uint128_t result = (__uint128_t)input;
37  return result;
38}
39