mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-26 20:51:11 +00:00
84 lines
2.3 KiB
C
84 lines
2.3 KiB
C
/* s_frexpl.c -- long double version of s_frexp.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
|
|
|
|
/*
|
|
* for non-zero x
|
|
* x = frexpl(arg,&exp);
|
|
* return a long double fp quantity x such that 0.5 <= |x| <1.0
|
|
* and the corresponding binary exponent "exp". That is
|
|
* arg = x*2^exp.
|
|
* If arg is inf, 0.0, or NaN, then frexpl(arg,&exp) returns arg
|
|
* with *exp=0.
|
|
*/
|
|
|
|
#include <math.h>
|
|
#include <math_private.h>
|
|
#include <math_ldbl_opt.h>
|
|
|
|
static const long double
|
|
two107 = 162259276829213363391578010288128.0; /* 0x4670000000000000, 0 */
|
|
|
|
long double __frexpl(long double x, int *eptr)
|
|
{
|
|
u_int64_t hx, lx, ix, ixl;
|
|
int64_t explo;
|
|
GET_LDOUBLE_WORDS64(hx,lx,x);
|
|
ixl = 0x7fffffffffffffffULL&lx;
|
|
ix = 0x7fffffffffffffffULL&hx;
|
|
*eptr = 0;
|
|
if(ix>=0x7ff0000000000000ULL||((ix|ixl)==0)) return x; /* 0,inf,nan */
|
|
if (ix<0x0010000000000000ULL) { /* subnormal */
|
|
x *= two107;
|
|
GET_LDOUBLE_MSW64(hx,x);
|
|
ix = hx&0x7fffffffffffffffULL;
|
|
*eptr = -107;
|
|
}
|
|
*eptr += (ix>>52)-1022;
|
|
|
|
if (ixl != 0ULL) {
|
|
explo = (ixl>>52) - (ix>>52) + 0x3fe;
|
|
if ((ixl&0x7ff0000000000000ULL) == 0LL) {
|
|
/* the lower double is a denomal so we need to correct its
|
|
mantissa and perhaps its exponent. */
|
|
int cnt;
|
|
|
|
if (sizeof (ixl) == sizeof (long))
|
|
cnt = __builtin_clzl (ixl);
|
|
else if ((ixl >> 32) != 0)
|
|
cnt = __builtin_clzl ((long) (ixl >> 32));
|
|
else
|
|
cnt = __builtin_clzl ((long) ixl) + 32;
|
|
cnt = cnt - 12;
|
|
lx = (lx&0x8000000000000000ULL) | ((explo-cnt)<<52)
|
|
| ((ixl<<(cnt+1))&0x000fffffffffffffULL);
|
|
} else
|
|
lx = (lx&0x800fffffffffffffULL) | (explo<<52);
|
|
} else
|
|
lx = 0ULL;
|
|
|
|
hx = (hx&0x800fffffffffffffULL) | 0x3fe0000000000000ULL;
|
|
SET_LDOUBLE_WORDS64(x,hx,lx);
|
|
return x;
|
|
}
|
|
#ifdef IS_IN_libm
|
|
long_double_symbol (libm, __frexpl, frexpl);
|
|
#else
|
|
long_double_symbol (libc, __frexpl, frexpl);
|
|
#endif
|