1//===-- lib/floatditf.c - integer -> 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 di_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_TF_MODE)
19COMPILER_RT_ABI fp_t __floatditf(di_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(x: 0);
26
27 // All other cases begin by extracting the sign and absolute value of a
28 rep_t sign = 0;
29 du_int aAbs = (du_int)a;
30 if (a < 0) {
31 sign = signBit;
32 aAbs = ~(du_int)a + 1U;
33 }
34
35 // Exponent of (fp_t)a is the width of abs(a).
36 const int exponent = (aWidth - 1) - __builtin_clzll(aAbs);
37 rep_t result;
38
39 // Shift a into the significand field, rounding if it is a right-shift
40 const int shift = significandBits - exponent;
41 result = (rep_t)aAbs << shift ^ implicitBit;
42
43 // Insert the exponent
44 result += (rep_t)(exponent + exponentBias) << significandBits;
45 // Insert the sign bit and return
46 return fromRep(x: result | sign);
47}
48
49#endif
50

source code of compiler-rt/lib/builtins/floatditf.c