// SPDX-License-Identifier: GPL-2.0-only
/* IEEE754 floating point arithmetic
 * double precision: common utilities
 */
/*
 * MIPS floating point support
 * Copyright (C) 1994-2000 Algorithmics Ltd.
 */

#include "ieee754sp.h"
#include "ieee754dp.h"

static inline union ieee754dp ieee754dp_nan_fsp(int xs, u64 xm)
{
        return builddp(xs, DP_EMAX + 1 + DP_EBIAS,
                       xm << (DP_FBITS - SP_FBITS));
}

union ieee754dp ieee754dp_fsp(union ieee754sp x)
{
        COMPXSP;

        EXPLODEXSP;

        ieee754_clearcx();

        FLUSHXSP;

        switch (xc) {
        case IEEE754_CLASS_SNAN:
                return ieee754dp_nanxcpt(ieee754dp_nan_fsp(xs, xm));

        case IEEE754_CLASS_QNAN:
                return ieee754dp_nan_fsp(xs, xm);

        case IEEE754_CLASS_INF:
                return ieee754dp_inf(xs);

        case IEEE754_CLASS_ZERO:
                return ieee754dp_zero(xs);

        case IEEE754_CLASS_DNORM:
                /* normalize */
                while ((xm >> SP_FBITS) == 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_FBITS - SP_FBITS));
}