1 //===-- lib/floatsisf.c - integer -> single-precision conversion --*- C -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements integer to single-precision conversion for the
11 // compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even
14 //===----------------------------------------------------------------------===//
16 #define SINGLE_PRECISION
21 ARM_EABI_FNALIAS(i2f, floatsisf)
23 fp_t __floatsisf(int a) {
25 const int aWidth = sizeof a * CHAR_BIT;
27 // Handle zero as a special case to protect clz
31 // All other cases begin by extracting the sign and absolute value of a
38 // Exponent of (fp_t)a is the width of abs(a).
39 const int exponent = (aWidth - 1) - __builtin_clz(a);
42 // Shift a into the significand field, rounding if it is a right-shift
43 if (exponent <= significandBits) {
44 const int shift = significandBits - exponent;
45 result = (rep_t)a << shift ^ implicitBit;
47 const int shift = exponent - significandBits;
48 result = (rep_t)a >> shift ^ implicitBit;
49 rep_t round = (rep_t)a << (typeWidth - shift);
50 if (round > signBit) result++;
51 if (round == signBit) result += result & 1;
54 // Insert the exponent
55 result += (rep_t)(exponent + exponentBias) << significandBits;
56 // Insert the sign bit and return
57 return fromRep(result | sign);