dp_fsp.c

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/* IEEE754 floating point arithmetic
 * double precision: common utilities
 */
/*
 * MIPS floating point support
 * Copyright (C) 1994-2000 Algorithmics Ltd.
 *
 * ########################################################################
 *
 *  This program is free software; you can distribute it and/or modify it
 *  under the terms of the GNU General Public License (Version 2) as
 *  published by the Free Software Foundation.
 *
 *  This program is distributed in the hope it will be useful, but WITHOUT
 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 *  for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
 *
 * ########################################################################
 */


#include "ieee754dp.h"

ieee754dp ieee754dp_fsp(ieee754sp x)
{
    COMPXSP;

    EXPLODEXSP;

    CLEARCX;

    FLUSHXSP;

    switch (xc) {
    case IEEE754_CLASS_SNAN:
        SETCX(IEEE754_INVALID_OPERATION);
        return ieee754dp_nanxcpt(ieee754dp_indef(), "fsp");
    case IEEE754_CLASS_QNAN:
        return ieee754dp_nanxcpt(builddp(xs,
                         DP_EMAX + 1 + DP_EBIAS,
                         ((u64) xm
                          << (DP_MBITS -
                              SP_MBITS))), "fsp",
                     x);
    case IEEE754_CLASS_INF:
        return ieee754dp_inf(xs);
    case IEEE754_CLASS_ZERO:
        return ieee754dp_zero(xs);
    case IEEE754_CLASS_DNORM:
        /* normalize */
        while ((xm >> SP_MBITS) == 0) {
            xm <<= 1;
            xe--;
        }
        break;
    case IEEE754_CLASS_NORM:
        break;
    }

    /* CAN'T possibly overflow,underflow, or need rounding
     */

    /* drop the hidden bit */
    xm &= ~SP_HIDDEN_BIT;

    return builddp(xs, xe + DP_EBIAS,
               (u64) xm << (DP_MBITS - SP_MBITS));
}