float128: Add strtof128, wcstof128, and related functions.
[glibc.git] / sysdeps / ieee754 / flt-32 / s_remquof.c
blob8e398dc6c54595507626dad5d6108333a5de7794
1 /* Compute remainder and a congruent to the quotient.
2 Copyright (C) 1997-2017 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 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.
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 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <http://www.gnu.org/licenses/>. */
20 #include <math.h>
22 #include <math_private.h>
25 static const float zero = 0.0;
28 float
29 __remquof (float x, float y, int *quo)
31 int32_t hx,hy;
32 u_int32_t sx;
33 int cquo, qs;
35 GET_FLOAT_WORD (hx, x);
36 GET_FLOAT_WORD (hy, y);
37 sx = hx & 0x80000000;
38 qs = sx ^ (hy & 0x80000000);
39 hy &= 0x7fffffff;
40 hx &= 0x7fffffff;
42 /* Purge off exception values. */
43 if (hy == 0)
44 return (x * y) / (x * y); /* y = 0 */
45 if ((hx >= 0x7f800000) /* x not finite */
46 || (hy > 0x7f800000)) /* y is NaN */
47 return (x * y) / (x * y);
49 if (hy <= 0x7dffffff)
50 x = __ieee754_fmodf (x, 8 * y); /* now x < 8y */
52 if ((hx - hy) == 0)
54 *quo = qs ? -1 : 1;
55 return zero * x;
58 x = fabsf (x);
59 y = fabsf (y);
60 cquo = 0;
62 if (hy <= 0x7e7fffff && x >= 4 * y)
64 x -= 4 * y;
65 cquo += 4;
67 if (hy <= 0x7effffff && x >= 2 * y)
69 x -= 2 * y;
70 cquo += 2;
73 if (hy < 0x01000000)
75 if (x + x > y)
77 x -= y;
78 ++cquo;
79 if (x + x >= y)
81 x -= y;
82 ++cquo;
86 else
88 float y_half = 0.5 * y;
89 if (x > y_half)
91 x -= y;
92 ++cquo;
93 if (x >= y_half)
95 x -= y;
96 ++cquo;
101 *quo = qs ? -cquo : cquo;
103 /* Ensure correct sign of zero result in round-downward mode. */
104 if (x == 0.0f)
105 x = 0.0f;
106 if (sx)
107 x = -x;
108 return x;
110 weak_alias (__remquof, remquof)