1 //===-- lib/fixsfsi.c - Single-precision -> integer conversion ----*- C -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements single-precision to integer conversion for the
11 // compiler-rt library. No range checking is performed; the behavior of this
12 // conversion is undefined for out of range values in the C standard.
13 //
14 //===----------------------------------------------------------------------===//
15
16 #define SINGLE_PRECISION
17 #include "fp_lib.h"
18
ARM_EABI_FNALIAS(f2iz,fixsfsi)19 ARM_EABI_FNALIAS(f2iz, fixsfsi)
20
21 COMPILER_RT_ABI int
22 __fixsfsi(fp_t a) {
23 // Break a into sign, exponent, significand
24 const rep_t aRep = toRep(a);
25 const rep_t aAbs = aRep & absMask;
26 const int sign = aRep & signBit ? -1 : 1;
27 const int exponent = (aAbs >> significandBits) - exponentBias;
28 const rep_t significand = (aAbs & significandMask) | implicitBit;
29
30 // If 0 < exponent < significandBits, right shift to get the result.
31 if ((unsigned int)exponent < significandBits) {
32 return sign * (significand >> (significandBits - exponent));
33 }
34
35 // If exponent is negative, the result is zero.
36 else if (exponent < 0) {
37 return 0;
38 }
39
40 // If significandBits < exponent, left shift to get the result. This shift
41 // may end up being larger than the type width, which incurs undefined
42 // behavior, but the conversion itself is undefined in that case, so
43 // whatever the compiler decides to do is fine.
44 else {
45 return sign * (significand << (exponent - significandBits));
46 }
47 }
48