1 //===-- lib/floatsidf.c - integer -> double-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 integer to double-precision conversion for the
10 // compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even
13 //===----------------------------------------------------------------------===//
15 #define DOUBLE_PRECISION
20 COMPILER_RT_ABI fp_t __floatsidf(int a) {
22 const int aWidth = sizeof a * CHAR_BIT;
24 // Handle zero as a special case to protect clz
28 // All other cases begin by extracting the sign and absolute value of a
35 // Exponent of (fp_t)a is the width of abs(a).
36 const int exponent = (aWidth - 1) - __builtin_clz(a);
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
42 const int shift = significandBits - exponent;
43 result = (rep_t)(unsigned int)a << shift ^ implicitBit;
45 // Insert the exponent
46 result += (rep_t)(exponent + exponentBias) << significandBits;
47 // Insert the sign bit and return
48 return fromRep(result | sign);
51 #if defined(__ARM_EABI__)
52 #if defined(COMPILER_RT_ARMHF_TARGET)
53 AEABI_RTABI fp_t __aeabi_i2d(int a) { return __floatsidf(a); }
55 COMPILER_RT_ALIAS(__floatsidf, __aeabi_i2d)