/*
 * $Id: math_scalbnf.c,v 1.2 2005-05-29 14:45:32 obarthel Exp $
 *
 * :ts=4
 *
 * Portable ISO 'C' (1994) runtime library for the Amiga computer
 * Copyright (c) 2002-2005 by Olaf Barthel <olsen@sourcery.han.de>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Neither the name of Olaf Barthel nor the names of contributors
 *     may be used to endorse or promote products derived from this
 *     software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 *
 * PowerPC math library based in part on work by Sun Microsystems
 * 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.
 *
 *
 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
 */

#ifndef _MATH_HEADERS_H
#include "math_headers.h"
#endif /* _MATH_HEADERS_H */

/****************************************************************************/

#if defined(FLOATING_POINT_SUPPORT)

/****************************************************************************/

#if INT_MAX > 50000
#define OVERFLOW_INT 50000
#else
#define OVERFLOW_INT 30000
#endif

static const float
two25   =  3.355443200e+07,	/* 0x4c000000 */
twom25  =  2.9802322388e-08,	/* 0x33000000 */
huge   = 1.0e+30,
tiny   = 1.0e-30;

float
scalbnf (float x, int n)
{
	LONG  k,ix;
	GET_FLOAT_WORD(ix,x);
        k = (ix&0x7f800000)>>23;		/* extract exponent */
        if (k==0) {				/* 0 or subnormal x */
            if ((ix&0x7fffffff)==0) return x; /* +-0 */
	    x *= two25;
	    GET_FLOAT_WORD(ix,x);
	    k = ((ix&0x7f800000)>>23) - 25; 
            if (n< -50000) return tiny*x; 	/*underflow*/
	    }
        if (k==0xff) return x+x;		/* NaN or Inf */
        k = k+n; 
        if (k >  0xfe) return copysignf(__inff(),x); /* overflow  */
        if (k > 0) 				/* normal result */
	    {SET_FLOAT_WORD(x,(ix&0x807fffffU)|(k<<23)); return x;}
        if (k <= -25) {
            if (n > OVERFLOW_INT) 	/* in case integer overflow in n+k */
		return copysignf(__inff(),x);/*overflow*/
	    else return tiny*copysignf(tiny,x);	/*underflow*/
	}
        k += 25;				/* subnormal result */
	SET_FLOAT_WORD(x,(ix&0x807fffffU)|(k<<23));
        return x*twom25;
}

/****************************************************************************/

#endif /* FLOATING_POINT_SUPPORT */
