projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| bc9f6000 UD |
1 | /* Compute remainder and a congruent to the quotient. |
| 2 | Copyright (C) 1997 Free Software Foundation, Inc. | |
| 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 | |
| 7 | modify it under the terms of the GNU Library General Public License as | |
| 8 | published by the Free Software Foundation; either version 2 of the | |
| 9 | License, or (at your option) any later version. | |
| 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 | |
| 14 | Library General Public License for more details. | |
| 15 | ||
| 16 | You should have received a copy of the GNU Library General Public | |
| 17 | License along with the GNU C Library; see the file COPYING.LIB. If not, | |
| 18 | write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
| 19 | Boston, MA 02111-1307, USA. */ | |
| 20 | ||
| 21 | #include <math.h> | |
| 22 | ||
| 23 | #include "math_private.h" | |
| 24 | ||
| 25 | ||
| 26 | static const float zero = 0.0; | |
| 27 | ||
| 28 | ||
| 29 | float | |
| 30 | __remquof (float x, float y, int *quo) | |
| 31 | { | |
| 32 | int32_t hx,hp; | |
| 33 | u_int32_t sx; | |
| 34 | int cquo; | |
| 35 | ||
| 36 | GET_FLOAT_WORD (hx, x); | |
| 37 | GET_FLOAT_WORD (hp, p); | |
| 38 | sx = hx & 0x80000000; | |
| 39 | qs = (sx ^ (hp & 0x80000000)) >> 31; | |
| 40 | hp &= 0x7fffffff; | |
| 41 | hx &= 0x7fffffff; | |
| 42 | ||
| 43 | /* Purge off exception values. */ | |
| 44 | if (hp == 0) | |
| 45 | return (x * p) / (x * p); /* p = 0 */ | |
| 46 | if ((hx >= 0x7f800000) /* x not finite */ | |
| 47 | || (hp > 0x7f800000)) /* p is NaN */ | |
| 48 | return (x * p) / (x * p); | |
| 49 | ||
| 50 | if (hp <= 0x7dffffff) | |
| 51 | { | |
| 52 | x = __ieee754_fmodf (x, 8 * p); /* now x < 8p */ | |
| 53 | ||
| 54 | if (fabs (x) >= 4 * fabs (p)) | |
| 55 | cquo += 4; | |
| 56 | } | |
| 57 | ||
| 58 | if ((hx - hp) == 0) | |
| 59 | { | |
| 60 | *quo = qs ? -1 : 1; | |
| 61 | return zero * x; | |
| 62 | } | |
| 63 | ||
| 64 | x = fabsf (x); | |
| 65 | p = fabsf (p); | |
| 66 | cquo = 0; | |
| 67 | ||
| 68 | if (x >= 2 * p) | |
| 69 | { | |
| 70 | x -= 4 * p; | |
| 71 | cquo += 2; | |
| 72 | } | |
| 73 | if (x >= p) | |
| 74 | { | |
| 75 | x -= 2 * p; | |
| 76 | ++cquo; | |
| 77 | } | |
| 78 | ||
| 79 | if (hp < 0x01000000) | |
| 80 | { | |
| 81 | if (x + x > p) | |
| 82 | { | |
| 83 | x -= p; | |
| 84 | if (x + x >= p) | |
| 85 | x -= p; | |
| 86 | } | |
| 87 | } | |
| 88 | else | |
| 89 | { | |
| 90 | float p_half = 0.5 * p; | |
| 91 | if(x > p_half) | |
| 92 | { | |
| 93 | x -= p; | |
| 94 | if (x >= p_half) | |
| 95 | x -= p; | |
| 96 | } | |
| 97 | } | |
| 98 | ||
| 99 | *quo = qs ? -cquo : cquo; | |
| 100 | ||
| 101 | GET_FLOAT_WORD (hx, x); | |
| 102 | SET_FLOAT_WORD (x, hx ^ sx); | |
| 103 | return x; | |
| 104 | } | |
| 105 | weak_alias (__remquof, remquof) |