1 //===-- lib/floatditf.c - integer -> quad-precision conversion ----*- C -*-===//
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
7 //===----------------------------------------------------------------------===//
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
13 //===----------------------------------------------------------------------===//
15 #define QUAD_PRECISION
18 #if defined(CRT_HAS_128BIT) && defined(CRT_LDBL_128BIT)
19 COMPILER_RT_ABI fp_t __floatditf(di_int a) {
21 const int aWidth = sizeof a * CHAR_BIT;
23 // Handle zero as a special case to protect clz
27 // All other cases begin by extracting the sign and absolute value of a
29 du_int aAbs = (du_int)a;
32 aAbs = ~(du_int)a + 1U;
35 // Exponent of (fp_t)a is the width of abs(a).
36 const int exponent = (aWidth - 1) - __builtin_clzll(aAbs);
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;
43 // Insert the exponent
44 result += (rep_t)(exponent + exponentBias) << significandBits;
45 // Insert the sign bit and return
46 return fromRep(result | sign);