projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| bc9f6000 | 1 | /* Compute remainder and a congruent to the quotient. |
| 568035b7 | 2 | Copyright (C) 1997-2013 Free Software Foundation, Inc. |
| bc9f6000 UD |
3 | This file is part of the GNU C Library. |
| 4 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. | |
| 5 | ||
| 6 | The GNU C Library is free software; you can redistribute it and/or | |
| 41bdb6e2 AJ |
7 | modify it under the terms of the GNU Lesser General Public |
| 8 | License as published by the Free Software Foundation; either | |
| 9 | version 2.1 of the License, or (at your option) any later version. | |
| bc9f6000 UD |
10 | |
| 11 | The GNU C Library is distributed in the hope that it will be useful, | |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 41bdb6e2 | 14 | Lesser General Public License for more details. |
| bc9f6000 | 15 | |
| 41bdb6e2 | 16 | You should have received a copy of the GNU Lesser General Public |
| 59ba27a6 PE |
17 | License along with the GNU C Library; if not, see |
| 18 | <http://www.gnu.org/licenses/>. */ | |
| bc9f6000 UD |
19 | |
| 20 | #include <math.h> | |
| 21 | ||
| 1ed0291c | 22 | #include <math_private.h> |
| bc9f6000 UD |
23 | |
| 24 | ||
| 63551311 | 25 | static const long double zero = 0.0; |
| bc9f6000 UD |
26 | |
| 27 | ||
| 28 | long double | |
| 63551311 | 29 | __remquol (long double x, long double p, int *quo) |
| bc9f6000 UD |
30 | { |
| 31 | int32_t ex,ep,hx,hp; | |
| 32 | u_int32_t sx,lx,lp; | |
| 63551311 | 33 | int cquo,qs; |
| bc9f6000 UD |
34 | |
| 35 | GET_LDOUBLE_WORDS (ex, hx, lx, x); | |
| 36 | GET_LDOUBLE_WORDS (ep, hp, lp, p); | |
| 37 | sx = ex & 0x8000; | |
| 38 | qs = (sx ^ (ep & 0x8000)) >> 15; | |
| 39 | ep &= 0x7fff; | |
| 40 | ex &= 0x7fff; | |
| 41 | ||
| 42 | /* Purge off exception values. */ | |
| 43 | if ((ep | hp | lp) == 0) | |
| 44 | return (x * p) / (x * p); /* p = 0 */ | |
| 45 | if ((ex == 0x7fff) /* x not finite */ | |
| 46 | || ((ep == 0x7fff) /* p is NaN */ | |
| 47 | && ((hp | lp) != 0))) | |
| 48 | return (x * p) / (x * p); | |
| 49 | ||
| 50 | if (ep <= 0x7ffb) | |
| 63551311 | 51 | x = __ieee754_fmodl (x, 8 * p); /* now x < 8p */ |
| bc9f6000 UD |
52 | |
| 53 | if (((ex - ep) | (hx - hp) | (lx - lp)) == 0) | |
| 54 | { | |
| 55 | *quo = qs ? -1 : 1; | |
| 56 | return zero * x; | |
| 57 | } | |
| 58 | ||
| 59 | x = fabsl (x); | |
| 60 | p = fabsl (p); | |
| 61 | cquo = 0; | |
| 62 | ||
| 63551311 | 63 | if (x >= 4 * p) |
| bc9f6000 UD |
64 | { |
| 65 | x -= 4 * p; | |
| 63551311 UD |
66 | cquo += 4; |
| 67 | } | |
| 68 | if (x >= 2 * p) | |
| 69 | { | |
| 70 | x -= 2 * p; | |
| bc9f6000 UD |
71 | cquo += 2; |
| 72 | } | |
| bc9f6000 UD |
73 | |
| 74 | if (ep < 0x0002) | |
| 75 | { | |
| 76 | if (x + x > p) | |
| 77 | { | |
| 78 | x -= p; | |
| d705269e | 79 | ++cquo; |
| bc9f6000 | 80 | if (x + x >= p) |
| 63551311 UD |
81 | { |
| 82 | x -= p; | |
| 83 | ++cquo; | |
| 84 | } | |
| bc9f6000 UD |
85 | } |
| 86 | } | |
| 87 | else | |
| 88 | { | |
| 89 | long double p_half = 0.5 * p; | |
| 63551311 | 90 | if (x > p_half) |
| bc9f6000 UD |
91 | { |
| 92 | x -= p; | |
| d705269e | 93 | ++cquo; |
| bc9f6000 | 94 | if (x >= p_half) |
| 63551311 UD |
95 | { |
| 96 | x -= p; | |
| 97 | ++cquo; | |
| 98 | } | |
| bc9f6000 UD |
99 | } |
| 100 | } | |
| 101 | ||
| 102 | *quo = qs ? -cquo : cquo; | |
| 103 | ||
| 63551311 UD |
104 | if (sx) |
| 105 | x = -x; | |
| bc9f6000 UD |
106 | return x; |
| 107 | } | |
| 108 | weak_alias (__remquol, remquol) |