2 Copyright (C) 2011-2012 Free Software Foundation, Inc.
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 fmod (double x, double y)
29 double q = - trunc (x / y);
30 double r = fma (q, y, x); /* = x + q * y, computed in one step */
31 /* Correct possible rounding errors in the quotient x / y. */
36 /* Expect 0 <= r < y. */
38 q += 1, r = fma (q, y, x);
40 q -= 1, r = fma (q, y, x);
44 /* Expect - y < r <= 0. */
46 q -= 1, r = fma (q, y, x);
48 q += 1, r = fma (q, y, x);
55 /* Expect 0 <= r < - y. */
57 q -= 1, r = fma (q, y, x);
59 q += 1, r = fma (q, y, x);
63 /* Expect y < r <= 0. */
65 q += 1, r = fma (q, y, x);
67 q -= 1, r = fma (q, y, x);