1//===-- lib/fixdfsi.c - Double-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 float to integer conversion for the
11// compiler-rt library.
12//
13//===----------------------------------------------------------------------===//
14
15#include "fp_lib.h"
16
17static inline fixint_t __fixint(fp_t a) {
18    const fixint_t fixint_max = (fixint_t)((~(fixuint_t)0) / 2);
19    const fixint_t fixint_min = -fixint_max - 1;
20    // Break a into sign, exponent, significand
21    const rep_t aRep = toRep(a);
22    const rep_t aAbs = aRep & absMask;
23    const fixint_t sign = aRep & signBit ? -1 : 1;
24    const int exponent = (aAbs >> significandBits) - exponentBias;
25    const rep_t significand = (aAbs & significandMask) | implicitBit;
26
27    // If exponent is negative, the result is zero.
28    if (exponent < 0)
29        return 0;
30
31    // If the value is too large for the integer type, saturate.
32    if ((unsigned)exponent >= sizeof(fixint_t) * CHAR_BIT)
33        return sign == 1 ? fixint_max : fixint_min;
34
35    // If 0 <= exponent < significandBits, right shift to get the result.
36    // Otherwise, shift left.
37    if (exponent < significandBits)
38        return sign * (significand >> (significandBits - exponent));
39    else
40        return sign * ((fixint_t)significand << (exponent - significandBits));
41}
42