Update.
[glibc.git] / sysdeps / libm-ieee754 / s_remquof.c
blob2ffd16c90329161b6e7fbfcca370cd3f150ca8f0
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 float zero = 0.0;
29 float
30 __remquof (float x, float y, int *quo)
32 int32_t hx,hy;
33 u_int32_t sx;
34 int cquo, qs;
36 GET_FLOAT_WORD (hx, x);
37 GET_FLOAT_WORD (hy, y);
38 sx = hx & 0x80000000;
39 qs = sx ^ (hy & 0x80000000);
40 hy &= 0x7fffffff;
41 hx &= 0x7fffffff;
43 /* Purge off exception values. */
44 if (hy == 0)
45 return (x * y) / (x * y); /* y = 0 */
46 if ((hx >= 0x7f800000) /* x not finite */
47 || (hy > 0x7f800000)) /* y is NaN */
48 return (x * y) / (x * y);
50 if (hy <= 0x7dffffff)
51 x = __ieee754_fmodf (x, 8 * y); /* now x < 8y */
53 if ((hx - hy) == 0)
55 *quo = qs ? -1 : 1;
56 return zero * x;
59 x = fabsf (x);
60 y = fabsf (y);
61 cquo = 0;
63 if (x >= 4 * y)
65 x -= 4 * y;
66 cquo += 4;
68 if (x >= 2 * y)
70 x -= 2 * y;
71 cquo += 2;
74 if (hy < 0x01000000)
76 if (x + x > y)
78 x -= y;
79 ++cquo;
80 if (x + x >= y)
82 x -= y;
83 ++cquo;
87 else
89 float y_half = 0.5 * y;
90 if (x > y_half)
92 x -= y;
93 ++cquo;
94 if (x >= y_half)
96 x -= y;
97 ++cquo;
102 *quo = qs ? -cquo : cquo;
104 if (sx)
105 x = -x;
106 return x;
108 weak_alias (__remquof, remquof)