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
);