| 1 | //===-- lib/fixdfsi.c - Double-precision -> integer conversion ----*- C -*-===// |
|---|---|
| 2 | // |
| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | // See https://llvm.org/LICENSE.txt for license information. |
| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | // |
| 7 | //===----------------------------------------------------------------------===// |
| 8 | // |
| 9 | // This file implements float to integer conversion for the |
| 10 | // compiler-rt library. |
| 11 | // |
| 12 | //===----------------------------------------------------------------------===// |
| 13 | |
| 14 | #include "fp_lib.h" |
| 15 | |
| 16 | static __inline fixint_t __fixint(fp_t a) { |
| 17 | const fixint_t fixint_max = (fixint_t)((~(fixuint_t)0) / 2); |
| 18 | const fixint_t fixint_min = -fixint_max - 1; |
| 19 | // Break a into sign, exponent, significand parts. |
| 20 | const rep_t aRep = toRep(x: a); |
| 21 | const rep_t aAbs = aRep & absMask; |
| 22 | const fixint_t sign = aRep & signBit ? -1 : 1; |
| 23 | const int exponent = (aAbs >> significandBits) - exponentBias; |
| 24 | const rep_t significand = (aAbs & significandMask) | implicitBit; |
| 25 | |
| 26 | // If exponent is negative, the result is zero. |
| 27 | if (exponent < 0) |
| 28 | return 0; |
| 29 | |
| 30 | // If the value is too large for the integer type, saturate. |
| 31 | if ((unsigned)exponent >= sizeof(fixint_t) * CHAR_BIT) |
| 32 | return sign == 1 ? fixint_max : fixint_min; |
| 33 | |
| 34 | // If 0 <= exponent < significandBits, right shift to get the result. |
| 35 | // Otherwise, shift left. |
| 36 | if (exponent < significandBits) |
| 37 | return (fixint_t)(sign * (significand >> (significandBits - exponent))); |
| 38 | else |
| 39 | return (fixint_t)(sign * ((fixuint_t)significand << (exponent - significandBits))); |
| 40 | } |
| 41 |