57 lines
1.4 KiB
C
Executable File
57 lines
1.4 KiB
C
Executable File
/* Copyright (c) 1988 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/* THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF AT&T */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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#ident "@(#)modf.c 1.10 93/11/12 SMI" /* SVr4.0 1.10.1.5 */
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/*LINTLIBRARY*/
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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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#ifdef __STDC__
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#pragma weak modf = _modf
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#endif
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#include "synonyms.h"
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#include <sys/types.h>
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#include <unistd.h>
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#include <signal.h>
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#include <values.h>
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#include <nan.h>
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double
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modf(value, iptr)
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double value; /* don't declare register, because of Is NAN orINF! */
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register double *iptr;
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{
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register double absvalue;
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if (IsNANorINF(value)) { /* check for NAN or INF (IEEE only) */
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*iptr = value;
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if (IsINF(value)) { /* infinity */
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return (value >= 0.0 ? 0.0 : -0.0); /* X3J11.1 spec. */
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}
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else { /* NaN */
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return (value); /* per XPG3 + X3J11.1 spec. */
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}
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}
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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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