/* @(#)s_frexp.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. | |
* ==================================================== | |
*/ | |
#include <LibConfig.h> | |
#include <sys/EfiCdefs.h> | |
#if defined(LIBM_SCCS) && !defined(lint) | |
__RCSID("$NetBSD: s_frexp.c,v 1.12 2002/05/26 22:01:56 wiz Exp $"); | |
#endif | |
/* | |
* for non-zero x | |
* x = frexp(arg,&exp); | |
* return a 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 frexp(arg,&exp) returns arg | |
* with *exp=0. | |
*/ | |
#include "math.h" | |
#include "math_private.h" | |
static const double | |
two54 = 1.80143985094819840000e+16; /* 0x43500000, 0x00000000 */ | |
double | |
frexp(double x, int *eptr) | |
{ | |
int32_t hx, ix, lx; | |
EXTRACT_WORDS(hx,lx,x); | |
ix = 0x7fffffff&hx; | |
*eptr = 0; | |
if(ix>=0x7ff00000||((ix|lx)==0)) return x; /* 0,inf,nan */ | |
if (ix<0x00100000) { /* subnormal */ | |
x *= two54; | |
GET_HIGH_WORD(hx,x); | |
ix = hx&0x7fffffff; | |
*eptr = -54; | |
} | |
*eptr += (ix>>20)-1022; | |
hx = (hx&0x800fffff)|0x3fe00000; | |
SET_HIGH_WORD(x,hx); | |
return x; | |
} |