41 lines
1.1 KiB
C
41 lines
1.1 KiB
C
#ifndef lint
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static char sccsid[] = "@(#)modf.c 1.1 94/10/31 SMI"; /* from ATT S5R3 */
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#endif
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/* The following is extracted from... */
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/* Copyright (c) 1984 AT&T */
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/* All Rights Reserved */
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/* THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF AT&T */
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/* The copyright notice above does not evidence any */
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/* actual or intended publication of such source code. */
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/*
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* modf(value, iptr) returns the signed fractional part of value
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* and stores the integer part indirectly through iptr.
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*
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*/
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#define MAXPOWTWO 4.503599627370496000E+15
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/* doubles >= MAXPOWTWO are already integers */
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double
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modf(value, iptr)
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double value;
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register double *iptr;
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{
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register double absvalue;
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if ((absvalue = (value >= 0.0) ? value : -value) >= MAXPOWTWO)
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*iptr = value; /* it must be an integer */
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else {
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*iptr = absvalue + MAXPOWTWO; /* shift fraction off right */
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*iptr -= MAXPOWTWO; /* shift back without fraction */
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while (*iptr > absvalue) /* above arithmetic might round */
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*iptr -= 1.0; /* test again just to be sure */
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if (value < 0.0)
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*iptr = -*iptr;
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}
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return (value - *iptr); /* signed fractional part */
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}
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