src/MSL_C.PPCEABI.bare.H/s_frexp.c


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/* @(#)s_frexp.c 1.3 95/01/04 */
/*
 * ====================================================
 * 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.
 * ====================================================
 */

/*
 * 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 "fdlibm.h"

#ifdef __STDC__
static const double
#else
static double
#endif
    two54 = 1.80143985094819840000e+16; /* 0x43500000, 0x00000000 */

#ifdef __STDC__
double frexp(double x, int* eptr)
#else
double frexp(x, eptr)
double x;
int* eptr;
#endif
{
  int hx, ix, lx;
  hx = __HI(x);
  ix = 0x7fffffff & hx;
  lx = __LO(x);
  *eptr = 0;
  if (ix >= 0x7ff00000 || ((ix | lx) == 0))
    return x;            /* 0,inf,nan */
  if (ix < 0x00100000) { /* subnormal */
    x *= two54;
    hx = __HI(x);
    ix = hx & 0x7fffffff;
    *eptr = -54;
  }
  *eptr += (ix >> 20) - 1022;
  hx = (hx & 0x800fffff) | 0x3fe00000;
  __HI(x) = hx;
  return x;
}