1//===-- lib/floatsisf.c - integer -> single-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 single-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 SINGLE_PRECISION
16#include "fp_lib.h"
17
18#include "int_lib.h"
19
20COMPILER_RT_ABI fp_t __floatsisf(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, rounding if it is a right-shift
40  if (exponent <= significandBits) {
41    const int shift = significandBits - exponent;
42    result = (rep_t)a << shift ^ implicitBit;
43  } else {
44    const int shift = exponent - significandBits;
45    result = (rep_t)a >> shift ^ implicitBit;
46    rep_t round = (rep_t)a << (typeWidth - shift);
47    if (round > signBit)
48      result++;
49    if (round == signBit)
50      result += result & 1;
51  }
52
53  // Insert the exponent
54  result += (rep_t)(exponent + exponentBias) << significandBits;
55  // Insert the sign bit and return
56  return fromRep(result | sign);
57}
58
59#if defined(__ARM_EABI__)
60#if defined(COMPILER_RT_ARMHF_TARGET)
61AEABI_RTABI fp_t __aeabi_i2f(int a) { return __floatsisf(a); }
62#else
63COMPILER_RT_ALIAS(__floatsisf, __aeabi_i2f)
64#endif
65#endif
66