projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| 423c2b9d | 1 | /* Round to integer type. flt-32 version. |
| 2b778ceb | 2 | Copyright (C) 2016-2021 Free Software Foundation, Inc. |
| 423c2b9d JM |
3 | This file is part of the GNU C Library. |
| 4 | ||
| 5 | The GNU C Library is free software; you can redistribute it and/or | |
| 6 | modify it under the terms of the GNU Lesser General Public | |
| 7 | License as published by the Free Software Foundation; either | |
| 8 | version 2.1 of the License, or (at your option) any later version. | |
| 9 | ||
| 10 | The GNU C Library is distributed in the hope that it will be useful, | |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 13 | Lesser General Public License for more details. | |
| 14 | ||
| 15 | You should have received a copy of the GNU Lesser General Public | |
| 16 | License along with the GNU C Library; if not, see | |
| 5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
| 423c2b9d JM |
18 | |
| 19 | #include <errno.h> | |
| 20 | #include <fenv.h> | |
| 21 | #include <math.h> | |
| 22 | #include <math_private.h> | |
| 2f49ce7d | 23 | #include <libm-alias-float.h> |
| 423c2b9d JM |
24 | #include <stdbool.h> |
| 25 | #include <stdint.h> | |
| 26 | ||
| 27 | #define BIAS 0x7f | |
| 28 | #define MANT_DIG 24 | |
| 29 | ||
| 30 | #if UNSIGNED | |
| 31 | # define RET_TYPE uintmax_t | |
| 32 | #else | |
| 33 | # define RET_TYPE intmax_t | |
| 34 | #endif | |
| 35 | ||
| 36 | #include <fromfp.h> | |
| 37 | ||
| 38 | RET_TYPE | |
| 39 | FUNC (float x, int round, unsigned int width) | |
| 40 | { | |
| 41 | if (width > INTMAX_WIDTH) | |
| 42 | width = INTMAX_WIDTH; | |
| 43 | uint32_t ix; | |
| 44 | GET_FLOAT_WORD (ix, x); | |
| 45 | bool negative = (ix & 0x80000000) != 0; | |
| 46 | if (width == 0) | |
| 47 | return fromfp_domain_error (negative, width); | |
| 48 | ix &= 0x7fffffff; | |
| 49 | if (ix == 0) | |
| 50 | return 0; | |
| 51 | int exponent = ix >> (MANT_DIG - 1); | |
| 52 | exponent -= BIAS; | |
| 53 | int max_exponent = fromfp_max_exponent (negative, width); | |
| 54 | if (exponent > max_exponent) | |
| 55 | return fromfp_domain_error (negative, width); | |
| 56 | ||
| 57 | ix &= ((1U << (MANT_DIG - 1)) - 1); | |
| 58 | ix |= 1U << (MANT_DIG - 1); | |
| 59 | uintmax_t uret; | |
| 60 | bool half_bit, more_bits; | |
| 61 | if (exponent >= MANT_DIG - 1) | |
| 62 | { | |
| 63 | uret = ix; | |
| 64 | uret <<= exponent - (MANT_DIG - 1); | |
| 65 | half_bit = false; | |
| 66 | more_bits = false; | |
| 67 | } | |
| 68 | else if (exponent >= -1) | |
| 69 | { | |
| 70 | uint32_t h = 1U << (MANT_DIG - 2 - exponent); | |
| 71 | half_bit = (ix & h) != 0; | |
| 72 | more_bits = (ix & (h - 1)) != 0; | |
| 73 | uret = ix >> (MANT_DIG - 1 - exponent); | |
| 74 | } | |
| 75 | else | |
| 76 | { | |
| 77 | uret = 0; | |
| 78 | half_bit = false; | |
| 79 | more_bits = true; | |
| 80 | } | |
| 81 | return fromfp_round_and_return (negative, uret, half_bit, more_bits, round, | |
| 82 | exponent, max_exponent, width); | |
| 83 | } |