Update.
[glibc.git] / sysdeps / libm-ieee754 / s_remquol.c
blob88ff298eb6387dc1f91051751e20d2530232cad1
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.
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.
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.
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. */
21 #include <math.h>
23 #include "math_private.h"
26 static const long double zero = 0.0;
29 long double
30 __remquol (long double x, long double p, int *quo)
32 int32_t ex,ep,hx,hp;
33 u_int32_t sx,lx,lp;
34 int cquo,qs;
36 GET_LDOUBLE_WORDS (ex, hx, lx, x);
37 GET_LDOUBLE_WORDS (ep, hp, lp, p);
38 sx = ex & 0x8000;
39 qs = (sx ^ (ep & 0x8000)) >> 15;
40 ep &= 0x7fff;
41 ex &= 0x7fff;
43 /* Purge off exception values. */
44 if ((ep | hp | lp) == 0)
45 return (x * p) / (x * p); /* p = 0 */
46 if ((ex == 0x7fff) /* x not finite */
47 || ((ep == 0x7fff) /* p is NaN */
48 && ((hp | lp) != 0)))
49 return (x * p) / (x * p);
51 if (ep <= 0x7ffb)
52 x = __ieee754_fmodl (x, 8 * p); /* now x < 8p */
54 if (((ex - ep) | (hx - hp) | (lx - lp)) == 0)
56 *quo = qs ? -1 : 1;
57 return zero * x;
60 x = fabsl (x);
61 p = fabsl (p);
62 cquo = 0;
64 if (x >= 4 * p)
66 x -= 4 * p;
67 cquo += 4;
69 if (x >= 2 * p)
71 x -= 2 * p;
72 cquo += 2;
75 if (ep < 0x0002)
77 if (x + x > p)
79 x -= p;
80 ++cquo;
81 if (x + x >= p)
83 x -= p;
84 ++cquo;
88 else
90 long double p_half = 0.5 * p;
91 if (x > p_half)
93 x -= p;
94 ++cquo;
95 if (x >= p_half)
97 x -= p;
98 ++cquo;
103 *quo = qs ? -cquo : cquo;
105 if (sx)
106 x = -x;
107 return x;
109 weak_alias (__remquol, remquol)