Commit 6c25be6e authored by Laurent Vivier's avatar Laurent Vivier
Browse files

target/m68k: implement ftentox 



Using a local m68k floatx80_tentox()
[copied from previous:
Written by Andreas Grabher for Previous, NeXT Computer Emulator.]

Signed-off-by: default avatarLaurent Vivier <laurent@vivier.eu>
Message-Id: <20180305203910.10391-9-laurent@vivier.eu>
parent 068f1615

target/m68k/fpu_helper.c

+5 −0
Original line number Diff line number Diff line
@@ -587,3 +587,8 @@ void HELPER(ftwotox)(CPUM68KState *env, FPReg *res, FPReg *val) 
{

    res->d = floatx80_twotox(val->d, &env->fp_status);

}



void HELPER(ftentox)(CPUM68KState *env, FPReg *res, FPReg *val)

{

    res->d = floatx80_tentox(val->d, &env->fp_status);

}

target/m68k/helper.h

+1 −0
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ DEF_HELPER_3(flog10, void, env, fp, fp) 
DEF_HELPER_3(flog2, void, env, fp, fp)

DEF_HELPER_3(fetox, void, env, fp, fp)

DEF_HELPER_3(ftwotox, void, env, fp, fp)

DEF_HELPER_3(ftentox, void, env, fp, fp)



DEF_HELPER_3(mac_move, void, env, i32, i32)

DEF_HELPER_3(macmulf, i64, env, i32, i32)

target/m68k/softfloat.c

+153 −0
Original line number Diff line number Diff line
@@ -1113,3 +1113,156 @@ floatx80 floatx80_twotox(floatx80 a, float_status *status) 
        return a;

    }

}



/*----------------------------------------------------------------------------

 | 10 to x

 *----------------------------------------------------------------------------*/



floatx80 floatx80_tentox(floatx80 a, float_status *status)

{

    flag aSign;

    int32_t aExp;

    uint64_t aSig;



    int8_t user_rnd_mode, user_rnd_prec;



    int32_t compact, n, j, l, m, m1;

    floatx80 fp0, fp1, fp2, fp3, adjfact, fact1, fact2;



    aSig = extractFloatx80Frac(a);

    aExp = extractFloatx80Exp(a);

    aSign = extractFloatx80Sign(a);



    if (aExp == 0x7FFF) {

        if ((uint64_t) (aSig << 1)) {

            return propagateFloatx80NaNOneArg(a, status);

        }

        if (aSign) {

            return packFloatx80(0, 0, 0);

        }

        return packFloatx80(0, floatx80_infinity.high,

                            floatx80_infinity.low);

    }



    if (aExp == 0 && aSig == 0) {

        return packFloatx80(0, one_exp, one_sig);

    }



    user_rnd_mode = status->float_rounding_mode;

    user_rnd_prec = status->floatx80_rounding_precision;

    status->float_rounding_mode = float_round_nearest_even;

    status->floatx80_rounding_precision = 80;



    fp0 = a;



    compact = floatx80_make_compact(aExp, aSig);



    if (compact < 0x3FB98000 || compact > 0x400B9B07) {

        /* |X| > 16480 LOG2/LOG10 or |X| < 2^(-70) */

        if (compact > 0x3FFF8000) { /* |X| > 16480 */

            status->float_rounding_mode = user_rnd_mode;

            status->floatx80_rounding_precision = user_rnd_prec;



            if (aSign) {

                return roundAndPackFloatx80(status->floatx80_rounding_precision,

                                            0, -0x1000, aSig, 0, status);

            } else {

                return roundAndPackFloatx80(status->floatx80_rounding_precision,

                                            0, 0x8000, aSig, 0, status);

            }

        } else { /* |X| < 2^(-70) */

            status->float_rounding_mode = user_rnd_mode;

            status->floatx80_rounding_precision = user_rnd_prec;



            a = floatx80_add(fp0, float32_to_floatx80(

                             make_float32(0x3F800000), status),

                             status); /* 1 + X */



            float_raise(float_flag_inexact, status);



            return a;

        }

    } else { /* 2^(-70) <= |X| <= 16480 LOG 2 / LOG 10 */

        fp1 = fp0; /* X */

        fp1 = floatx80_mul(fp1, float64_to_floatx80(

                           make_float64(0x406A934F0979A371),

                           status), status); /* X*64*LOG10/LOG2 */

        n = floatx80_to_int32(fp1, status); /* N=INT(X*64*LOG10/LOG2) */

        fp1 = int32_to_floatx80(n, status);



        j = n & 0x3F;

        l = n / 64; /* NOTE: this is really arithmetic right shift by 6 */

        if (n < 0 && j) {

            /* arithmetic right shift is division and

             * round towards minus infinity

             */

            l--;

        }

        m = l / 2; /* NOTE: this is really arithmetic right shift by 1 */

        if (l < 0 && (l & 1)) {

            /* arithmetic right shift is division and

             * round towards minus infinity

             */

            m--;

        }

        m1 = l - m;

        m1 += 0x3FFF; /* ADJFACT IS 2^(M') */



        adjfact = packFloatx80(0, m1, one_sig);

        fact1 = exp2_tbl[j];

        fact1.high += m;

        fact2.high = exp2_tbl2[j] >> 16;

        fact2.high += m;

        fact2.low = (uint64_t)(exp2_tbl2[j] & 0xFFFF);

        fact2.low <<= 48;



        fp2 = fp1; /* N */

        fp1 = floatx80_mul(fp1, float64_to_floatx80(

                           make_float64(0x3F734413509F8000), status),

                           status); /* N*(LOG2/64LOG10)_LEAD */

        fp3 = packFloatx80(1, 0x3FCD, LIT64(0xC0219DC1DA994FD2));

        fp2 = floatx80_mul(fp2, fp3, status); /* N*(LOG2/64LOG10)_TRAIL */

        fp0 = floatx80_sub(fp0, fp1, status); /* X - N L_LEAD */

        fp0 = floatx80_sub(fp0, fp2, status); /* X - N L_TRAIL */

        fp2 = packFloatx80(0, 0x4000, LIT64(0x935D8DDDAAA8AC17)); /* LOG10 */

        fp0 = floatx80_mul(fp0, fp2, status); /* R */



        /* EXPR */

        fp1 = floatx80_mul(fp0, fp0, status); /* S = R*R */

        fp2 = float64_to_floatx80(make_float64(0x3F56C16D6F7BD0B2),

                                  status); /* A5 */

        fp3 = float64_to_floatx80(make_float64(0x3F811112302C712C),

                                  status); /* A4 */

        fp2 = floatx80_mul(fp2, fp1, status); /* S*A5 */

        fp3 = floatx80_mul(fp3, fp1, status); /* S*A4 */

        fp2 = floatx80_add(fp2, float64_to_floatx80(

                           make_float64(0x3FA5555555554CC1), status),

                           status); /* A3+S*A5 */

        fp3 = floatx80_add(fp3, float64_to_floatx80(

                           make_float64(0x3FC5555555554A54), status),

                           status); /* A2+S*A4 */

        fp2 = floatx80_mul(fp2, fp1, status); /* S*(A3+S*A5) */

        fp3 = floatx80_mul(fp3, fp1, status); /* S*(A2+S*A4) */

        fp2 = floatx80_add(fp2, float64_to_floatx80(

                           make_float64(0x3FE0000000000000), status),

                           status); /* A1+S*(A3+S*A5) */

        fp3 = floatx80_mul(fp3, fp0, status); /* R*S*(A2+S*A4) */



        fp2 = floatx80_mul(fp2, fp1, status); /* S*(A1+S*(A3+S*A5)) */

        fp0 = floatx80_add(fp0, fp3, status); /* R+R*S*(A2+S*A4) */

        fp0 = floatx80_add(fp0, fp2, status); /* EXP(R) - 1 */



        fp0 = floatx80_mul(fp0, fact1, status);

        fp0 = floatx80_add(fp0, fact2, status);

        fp0 = floatx80_add(fp0, fact1, status);



        status->float_rounding_mode = user_rnd_mode;

        status->floatx80_rounding_precision = user_rnd_prec;



        a = floatx80_mul(fp0, adjfact, status);



        float_raise(float_flag_inexact, status);



        return a;

    }

}

target/m68k/softfloat.h

+1 −0
Original line number Diff line number Diff line
@@ -33,4 +33,5 @@ floatx80 floatx80_log10(floatx80 a, float_status *status); 
floatx80 floatx80_log2(floatx80 a, float_status *status);

floatx80 floatx80_etox(floatx80 a, float_status *status);

floatx80 floatx80_twotox(floatx80 a, float_status *status);

floatx80 floatx80_tentox(floatx80 a, float_status *status);

#endif

target/m68k/translate.c

+3 −0
Original line number Diff line number Diff line
@@ -5063,6 +5063,9 @@ DISAS_INSN(fpu) 
    case 0x11: /* ftwotox */

        gen_helper_ftwotox(cpu_env, cpu_dest, cpu_src);

        break;

    case 0x12: /* ftentox */

        gen_helper_ftentox(cpu_env, cpu_dest, cpu_src);

        break;

    case 0x14: /* flogn */

        gen_helper_flogn(cpu_env, cpu_dest, cpu_src);

        break;