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 |
|
|
|
17 |
|
|
static __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 |
|
|
} |