source: vendor/FreeBSD-msun/current/src/s_frexpf.c

/* s_frexpf.c -- float version of s_frexp.c.
 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
 */

/*
 * ====================================================
 * 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.
 * ====================================================
 */

#ifndef lint
static char rcsid[] = "$FreeBSD: src/lib/msun/src/s_frexpf.c,v 1.8 2002/05/28 18:15:04 alfred Exp $";
#endif

#include "math.h"
#include "math_private.h"

static const float
two25 =  3.3554432000e+07; /* 0x4c000000 */

float
frexpf(float x, int *eptr)
{
        int32_t hx,ix;
        GET_FLOAT_WORD(hx,x);
        ix = 0x7fffffff&hx;
        *eptr = 0;
        if(ix>=0x7f800000||(ix==0)) return x;   /* 0,inf,nan */
        if (ix<0x00800000) {            /* subnormal */
            x *= two25;
            GET_FLOAT_WORD(hx,x);
            ix = hx&0x7fffffff;
            *eptr = -25;
        }
        *eptr += (ix>>23)-126;
        hx = (hx&0x807fffff)|0x3f000000;
        *(int*)&x = hx;
        return x;
}