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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>
#include <stdint.h>
static const double one = 1.0;
double
__modf(double x, double *iptr)
{
int64_t i0;
int32_t j0;
EXTRACT_WORDS64(i0,x);
j0 = ((i0>>52)&0x7ff)-0x3ff; /* exponent of x */
if(j0<52) { /* integer part in x */
if(j0<0) { /* |x|<1 */
/* *iptr = +-0 */
INSERT_WORDS64(*iptr,i0&UINT64_C(0x8000000000000000));
return x;
} else {
uint64_t i = UINT64_C(0x000fffffffffffff)>>j0;
if((i0&i)==0) { /* x is integral */
*iptr = x;
/* return +-0 */
INSERT_WORDS64(x,i0&UINT64_C(0x8000000000000000));
return x;
} else {
INSERT_WORDS64(*iptr,i0&(~i));
return x - *iptr;
}
}
} else { /* no fraction part */
*iptr = x*one;
/* We must handle NaNs separately. */
if (j0 == 0x400 && (i0 & UINT64_C(0xfffffffffffff)))
return x*one;
INSERT_WORDS64(x,i0&UINT64_C(0x8000000000000000)); /* return +-0 */
return x;
}
}
#ifndef __modf
libm_alias_double (__modf, modf)
#endif
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