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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"
static const double one = 1.0;
double modf(double x, double *iptr)
{
int32_t i0,i1,_j0;
u_int32_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 (_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 = ((u_int32_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;
}
}
}
libm_hidden_def(modf)
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