1//===-- lib/floatunditf.c - uint -> quad-precision conversion -----*- 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 du_int to quad-precision conversion for the
10// compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even
11// mode.
12//
13//===----------------------------------------------------------------------===//
14
15#define QUAD_PRECISION
16#include "fp_lib.h"
17
18#if defined(CRT_HAS_128BIT) && defined(CRT_LDBL_128BIT)
19COMPILER_RT_ABI fp_t __floatunditf(du_int a) {
20
21  const int aWidth = sizeof a * CHAR_BIT;
22
23  // Handle zero as a special case to protect clz
24  if (a == 0)
25    return fromRep(0);
26
27  // Exponent of (fp_t)a is the width of abs(a).
28  const int exponent = (aWidth - 1) - __builtin_clzll(a);
29  rep_t result;
30
31  // Shift a into the significand field and clear the implicit bit.
32  const int shift = significandBits - exponent;
33  result = (rep_t)a << shift ^ implicitBit;
34
35  // Insert the exponent
36  result += (rep_t)(exponent + exponentBias) << significandBits;
37  return fromRep(result);
38}
39
40#endif
41