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-rw-r--r--sysdeps/libm-ieee754/s_remquo.c106
1 files changed, 106 insertions, 0 deletions
diff --git a/sysdeps/libm-ieee754/s_remquo.c b/sysdeps/libm-ieee754/s_remquo.c
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+/* Compute remainder and a congruent to the quotient.
+ Copyright (C) 1997 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include <math.h>
+
+#include "math_private.h"
+
+
+static const double zero = 0.0;
+
+
+double
+__remquo (double x, double y, int *quo)
+{
+ int32_t hx,hp;
+ u_int32_t sx,lx,lp;
+ int cquo;
+
+ EXTRACT_WORDS (hx, lx, x);
+ EXTRACT_WORDS (hp, lp, p);
+ sx = hx & 0x80000000;
+ qs = (sx ^ (hp & 0x80000000)) >> 31;
+ hp &= 0x7fffffff;
+ hx &= 0x7fffffff;
+
+ /* Purge off exception values. */
+ if ((hp | lp) == 0)
+ return (x * p) / (x * p); /* p = 0 */
+ if ((hx >= 0x7ff00000) /* x not finite */
+ || ((hp >= 0x7ff00000) /* p is NaN */
+ && (((hp - 0x7ff00000) | lp) != 0)))
+ return (x * p) / (x * p);
+
+ if (hp <= 0x7fbfffff)
+ {
+ x = __ieee754_fmod (x, 8 * p); /* now x < 8p */
+
+ if (fabs (x) >= 4 * fabs (p))
+ cquo += 4;
+ }
+
+ if (((hx - hp) | (lx - lp)) == 0)
+ {
+ *quo = qs ? -1 : 1;
+ return zero * x;
+ }
+
+ x = fabs (x);
+ p = fabs (p);
+ cquo = 0;
+
+ if (x >= 2 * p)
+ {
+ x -= 4 * p;
+ cquo += 2;
+ }
+ if (x >= p)
+ {
+ x -= 2 * p;
+ ++cquo;
+ }
+
+ if (hp < 0x00200000)
+ {
+ if (x + x > p)
+ {
+ x -= p;
+ if (x + x >= p)
+ x -= p;
+ }
+ }
+ else
+ {
+ double p_half = 0.5 * p;
+ if(x > p_half)
+ {
+ x -= p;
+ if (x >= p_half)
+ x -= p;
+ }
+ }
+
+ *quo = qs ? -cquo : cquo;
+
+ GET_HIGH_WORD (hx, x);
+ SET_HIGH_WORD (x, hx ^ sx);
+ return x;
+}
+weak_alias (__remquo, remquo)