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/* @(#)s_modf.c 5.1 93/09/24 */
/*
* ====================================================
* 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.
* ====================================================
*/
/*
* modfl(long double x, long 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 long double one = 1.0;
long double
modfl(long double x, long double *iptr)
{
int32_t i0,i1,jj0;
u_int32_t i,se;
GET_LDOUBLE_WORDS(se,i0,i1,x);
jj0 = (se&0x7fff)-0x3fff; /* exponent of x */
if(jj0<32) { /* integer part in high x */
if(jj0<0) { /* |x|<1 */
SET_LDOUBLE_WORDS(*iptr,se&0x8000,0,0); /* *iptr = +-0 */
return x;
} else {
i = (0x7fffffff)>>jj0;
if(((i0&i)|i1)==0) { /* x is integral */
*iptr = x;
SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */
return x;
} else {
SET_LDOUBLE_WORDS(*iptr,se,i0&(~i),0);
return x - *iptr;
}
}
} else if (jj0>63) { /* no fraction part */
*iptr = x*one;
/* We must handle NaNs separately. */
if (jj0 == 0x4000 && ((i0 & 0x7fffffff) | i1))
return x*one;
SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */
return x;
} else { /* fraction part in low x */
i = ((u_int32_t)(0x7fffffff))>>(jj0-32);
if((i1&i)==0) { /* x is integral */
*iptr = x;
SET_LDOUBLE_WORDS(x,se&0x8000,0,0); /* return +-0 */
return x;
} else {
SET_LDOUBLE_WORDS(*iptr,se,i0,i1&(~i));
return x - *iptr;
}
}
}
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