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

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

static inline union ieee754sp ieee754sp_nan_fdp(int xs, u64 xm)
{
        return buildsp(xs, SP_EMAX + 1 + SP_EBIAS,
                       xm >> (DP_FBITS - SP_FBITS));
}

union ieee754sp ieee754sp_fdp(union ieee754dp x)
{
        union ieee754sp y;
        u32 rm;

        COMPXDP;
        COMPYSP;

        EXPLODEXDP;

        ieee754_clearcx();

        FLUSHXDP;

        switch (xc) {
        case IEEE754_CLASS_SNAN:
                x = ieee754dp_nanxcpt(x);
                EXPLODEXDP;
                fallthrough;
        case IEEE754_CLASS_QNAN:
                y = ieee754sp_nan_fdp(xs, xm);
                if (!ieee754_csr.nan2008) {
                        EXPLODEYSP;
                        if (!ieee754_class_nan(yc))
                                y = ieee754sp_indef();
                }
                return y;

        case IEEE754_CLASS_INF:
                return ieee754sp_inf(xs);

        case IEEE754_CLASS_ZERO:
                return ieee754sp_zero(xs);

        case IEEE754_CLASS_DNORM:
                /* can't possibly be sp representable */
                ieee754_setcx(IEEE754_UNDERFLOW);
                ieee754_setcx(IEEE754_INEXACT);
                if ((ieee754_csr.rm == FPU_CSR_RU && !xs) ||
                                (ieee754_csr.rm == FPU_CSR_RD && xs))
                        return ieee754sp_mind(xs);
                return ieee754sp_zero(xs);

        case IEEE754_CLASS_NORM:
                break;
        }

        /*
         * Convert from DP_FBITS to SP_FBITS+3 with sticky right shift.
         */
        rm = (xm >> (DP_FBITS - (SP_FBITS + 3))) |
             ((xm << (64 - (DP_FBITS - (SP_FBITS + 3)))) != 0);

        return ieee754sp_format(xs, xe, rm);
}