1//===-- lib/floatsidf.c - integer -> double-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 integer to double-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 DOUBLE_PRECISION
16#include "fp_lib.h"
17
18#include "int_lib.h"
19
20COMPILER_RT_ABI fp_t __floatsidf(int a) {
21
22  const int aWidth = sizeof a * CHAR_BIT;
23
24  // Handle zero as a special case to protect clz
25  if (a == 0)
26    return fromRep(0);
27
28  // All other cases begin by extracting the sign and absolute value of a
29  rep_t sign = 0;
30  if (a < 0) {
31    sign = signBit;
32    a = -a;
33  }
34
35  // Exponent of (fp_t)a is the width of abs(a).
36  const int exponent = (aWidth - 1) - __builtin_clz(a);
37  rep_t result;
38
39  // Shift a into the significand field and clear the implicit bit.  Extra
40  // cast to unsigned int is necessary to get the correct behavior for
41  // the input INT_MIN.
42  const int shift = significandBits - exponent;
43  result = (rep_t)(unsigned int)a << shift ^ implicitBit;
44
45  // Insert the exponent
46  result += (rep_t)(exponent + exponentBias) << significandBits;
47  // Insert the sign bit and return
48  return fromRep(result | sign);
49}
50
51#if defined(__ARM_EABI__)
52#if defined(COMPILER_RT_ARMHF_TARGET)
53AEABI_RTABI fp_t __aeabi_i2d(int a) { return __floatsidf(a); }
54#else
55COMPILER_RT_ALIAS(__floatsidf, __aeabi_i2d)
56#endif
57#endif
58