// SPDX-License-Identifier: GPL-2.0-or-later
/*
    NetWinder Floating Point Emulator
    (c) Rebel.COM, 1998,1999

    Direct questions, comments to Scott Bambrough <scottb@netwinder.org>

*/

#include "fpa11.h"
#include "softfloat.h"
#include "fpopcode.h"

union float64_components {
        float64 f64;
        unsigned int i[2];
};

float64 float64_exp(float64 Fm);
float64 float64_ln(float64 Fm);
float64 float64_sin(float64 rFm);
float64 float64_cos(float64 rFm);
float64 float64_arcsin(float64 rFm);
float64 float64_arctan(float64 rFm);
float64 float64_log(float64 rFm);
float64 float64_tan(float64 rFm);
float64 float64_arccos(float64 rFm);
float64 float64_pow(float64 rFn, float64 rFm);
float64 float64_pol(float64 rFn, float64 rFm);

static float64 float64_rsf(struct roundingData *roundData, float64 rFn, float64 rFm)
{
        return float64_sub(roundData, rFm, rFn);
}

static float64 float64_rdv(struct roundingData *roundData, float64 rFn, float64 rFm)
{
        return float64_div(roundData, rFm, rFn);
}

static float64 (*const dyadic_double[16])(struct roundingData*, float64 rFn, float64 rFm) = {
        [ADF_CODE >> 20] = float64_add,
        [MUF_CODE >> 20] = float64_mul,
        [SUF_CODE >> 20] = float64_sub,
        [RSF_CODE >> 20] = float64_rsf,
        [DVF_CODE >> 20] = float64_div,
        [RDF_CODE >> 20] = float64_rdv,
        [RMF_CODE >> 20] = float64_rem,

        /* strictly, these opcodes should not be implemented */
        [FML_CODE >> 20] = float64_mul,
        [FDV_CODE >> 20] = float64_div,
        [FRD_CODE >> 20] = float64_rdv,
};

static float64 float64_mvf(struct roundingData *roundData,float64 rFm)
{
        return rFm;
}

static float64 float64_mnf(struct roundingData *roundData,float64 rFm)
{
        union float64_components u;

        u.f64 = rFm;
#ifdef __ARMEB__
        u.i[0] ^= 0x80000000;
#else
        u.i[1] ^= 0x80000000;
#endif

        return u.f64;
}

static float64 float64_abs(struct roundingData *roundData,float64 rFm)
{
        union float64_components u;

        u.f64 = rFm;
#ifdef __ARMEB__
        u.i[0] &= 0x7fffffff;
#else
        u.i[1] &= 0x7fffffff;
#endif

        return u.f64;
}

static float64 (*const monadic_double[16])(struct roundingData *, float64 rFm) = {
        [MVF_CODE >> 20] = float64_mvf,
        [MNF_CODE >> 20] = float64_mnf,
        [ABS_CODE >> 20] = float64_abs,
        [RND_CODE >> 20] = float64_round_to_int,
        [URD_CODE >> 20] = float64_round_to_int,
        [SQT_CODE >> 20] = float64_sqrt,
        [NRM_CODE >> 20] = float64_mvf,
};

unsigned int DoubleCPDO(struct roundingData *roundData, const unsigned int opcode, FPREG * rFd)
{
        FPA11 *fpa11 = GET_FPA11();
        float64 rFm;
        unsigned int Fm, opc_mask_shift;

        Fm = getFm(opcode);
        if (CONSTANT_FM(opcode)) {
                rFm = getDoubleConstant(Fm);
        } else {
                switch (fpa11->fType[Fm]) {
                case typeSingle:
                        rFm = float32_to_float64(fpa11->fpreg[Fm].fSingle);
                        break;

                case typeDouble:
                        rFm = fpa11->fpreg[Fm].fDouble;
                        break;

                default:
                        return 0;
                }
        }

        opc_mask_shift = (opcode & MASK_ARITHMETIC_OPCODE) >> 20;
        if (!MONADIC_INSTRUCTION(opcode)) {
                unsigned int Fn = getFn(opcode);
                float64 rFn;

                switch (fpa11->fType[Fn]) {
                case typeSingle:
                        rFn = float32_to_float64(fpa11->fpreg[Fn].fSingle);
                        break;

                case typeDouble:
                        rFn = fpa11->fpreg[Fn].fDouble;
                        break;

                default:
                        return 0;
                }

                if (dyadic_double[opc_mask_shift]) {
                        rFd->fDouble = dyadic_double[opc_mask_shift](roundData, rFn, rFm);
                } else {
                        return 0;
                }
        } else {
                if (monadic_double[opc_mask_shift]) {
                        rFd->fDouble = monadic_double[opc_mask_shift](roundData, rFm);
                } else {
                        return 0;
                }
        }

        return 1;
}