35 lines
627 B
C
35 lines
627 B
C
/* fmod function */
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/* Author Robert R. Hall (hall@crach.cts.com) */
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/* $Id$ */
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#include <math.h>
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#include <errno.h>
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double
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(fmod)(double x, double y)
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{ /* compute fmod(x, y) */
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double t;
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int n, neg;
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int ychar, xchar;
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if (y == 0.0) {
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errno = EDOM;
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return 0.0;
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}
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/* fmod(finite, finite) */
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if (y < 0.0) y = -y;
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if (x < 0.0) x = -x, neg = 1;
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else neg = 0;
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t = frexp(y, &ychar);
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/* substract |y| until |x| < |y| */
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t = frexp(x, &xchar);
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for (n = xchar - ychar; 0 <= n; --n) {
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/* try to substract |y|*2^n */
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t = ldexp(y, n);
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if (t <= x) x -= t;
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}
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return (neg ? -x : x);
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}
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