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/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
/*
* modf(double x, double *iptr)
* return fraction part of x, and return x's integral part in *iptr.
* Method:
* Bit twiddling.
*
* Exception:
* No exception.
*/
#include <math.h>
#include <math_private.h>
#include <libm-alias-double.h>
static const double one = 1.0;
double
__modf (double x, double *iptr)
{
int32_t i0, i1, j0;
uint32_t i;
EXTRACT_WORDS (i0, i1, x);
j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; /* exponent of x */
if (j0 < 20) /* integer part in high x */
{
if (j0 < 0) /* |x|<1 */
{
INSERT_WORDS (*iptr, i0 & 0x80000000, 0); /* *iptr = +-0 */
return x;
}
else
{
i = (0x000fffff) >> j0;
if (((i0 & i) | i1) == 0) /* x is integral */
{
*iptr = x;
INSERT_WORDS (x, i0 & 0x80000000, 0); /* return +-0 */
return x;
}
else
{
INSERT_WORDS (*iptr, i0 & (~i), 0);
return x - *iptr;
}
}
}
else if (__glibc_unlikely (j0 > 51)) /* no fraction part */
{
*iptr = x * one;
/* We must handle NaNs separately. */
if (j0 == 0x400 && ((i0 & 0xfffff) | i1))
return x * one;
INSERT_WORDS (x, i0 & 0x80000000, 0); /* return +-0 */
return x;
}
else /* fraction part in low x */
{
i = ((uint32_t) (0xffffffff)) >> (j0 - 20);
if ((i1 & i) == 0) /* x is integral */
{
*iptr = x;
INSERT_WORDS (x, i0 & 0x80000000, 0); /* return +-0 */
return x;
}
else
{
INSERT_WORDS (*iptr, i0, i1 & (~i));
return x - *iptr;
}
}
}
#ifndef __modf
libm_alias_double (__modf, modf)
#endif
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