/* s_modfl.c -- long double version of s_modf.c.
* Conversion to IEEE quad long double by Jakub Jelinek,
[email protected].
*/
/*
* ====================================================
* 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.
* ====================================================
*/
#if defined(LIBM_SCCS) && !defined(lint)
static char rcsid[] = "NetBSD: ";
#endif
/*
* modfq(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 "quadmath-imp.h"
static const __float128 one = 1.0;
__float128 modfq(__float128 x, __float128 *iptr)
{
int64_t i0,i1,j0;
uint64_t i;
GET_FLT128_WORDS64(i0,i1,x);
j0 = ((i0>>48)&0x7fff)-0x3fff; /* exponent of x */
if(j0<48) { /* integer part in high x */
if(j0<0) { /* |x|<1 */
/* *iptr = +-0 */
SET_FLT128_WORDS64(*iptr,i0&0x8000000000000000ULL,0);
return x;
} else {
i = (0x0000ffffffffffffLL)>>j0;
if(((i0&i)|i1)==0) { /* x is integral */
*iptr = x;
/* return +-0 */
SET_FLT128_WORDS64(x,i0&0x8000000000000000ULL,0);
return x;
} else {
SET_FLT128_WORDS64(*iptr,i0&(~i),0);
return x - *iptr;
}
}
} else if (j0>111) { /* no fraction part */
*iptr = x*one;
/* We must handle NaNs separately. */
if (j0 == 0x4000 && ((i0 & 0x0000ffffffffffffLL) | i1))
return x*one;
/* return +-0 */
SET_FLT128_WORDS64(x,i0&0x8000000000000000ULL,0);
return x;
} else { /* fraction part in low x */
i = -1ULL>>(j0-48);
if((i1&i)==0) { /* x is integral */
*iptr = x;
/* return +-0 */
SET_FLT128_WORDS64(x,i0&0x8000000000000000ULL,0);
return x;
} else {
SET_FLT128_WORDS64(*iptr,i0,i1&(~i));
return x - *iptr;
}
}
}
