s_frexpf.c

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

#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;
}