mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-30 08:40:07 +00:00
80 lines
2.1 KiB
C
80 lines
2.1 KiB
C
/* s_modfl.c -- long double version of s_modf.c.
|
|
* Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
|
|
*/
|
|
|
|
/*
|
|
* ====================================================
|
|
* 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
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
int64_t i0,i1,j0;
|
|
u_int64_t i;
|
|
GET_LDOUBLE_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_LDOUBLE_WORDS64(*iptr,i0&0x8000000000000000ULL,0);
|
|
return x;
|
|
} else {
|
|
i = (0x0000ffffffffffffLL)>>j0;
|
|
if(((i0&i)|i1)==0) { /* x is integral */
|
|
*iptr = x;
|
|
/* return +-0 */
|
|
SET_LDOUBLE_WORDS64(x,i0&0x8000000000000000ULL,0);
|
|
return x;
|
|
} else {
|
|
SET_LDOUBLE_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_LDOUBLE_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_LDOUBLE_WORDS64(x,i0&0x8000000000000000ULL,0);
|
|
return x;
|
|
} else {
|
|
SET_LDOUBLE_WORDS64(*iptr,i0,i1&(~i));
|
|
return x - *iptr;
|
|
}
|
|
}
|
|
}
|
|
weak_alias (__modfl, modfl)
|