Commit 94933df0 authored by Richard Henderson's avatar Richard Henderson
Browse files

fpu/softfloat: Canonicalize NaN fraction 



Shift the NaN fraction to a canonical position, much like we
do for the fraction of normal numbers.  This will facilitate
manipulation of NaNs within the shared code paths.

Tested-by: default avatarAlex Bennée <alex.bennee@linaro.org>
Reviewed-by: default avatarAlex Bennée <alex.bennee@linaro.org>
Reviewed-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: default avatarRichard Henderson <richard.henderson@linaro.org>
parent 0664335a

fpu/softfloat.c

+6 −1
Original line number Diff line number Diff line
@@ -330,10 +330,11 @@ static FloatParts canonicalize(FloatParts part, const FloatFmt *parm, 
        if (part.frac == 0) {

            part.cls = float_class_inf;

        } else {

            part.frac <<= parm->frac_shift;

#ifdef NO_SIGNALING_NANS

            part.cls = float_class_qnan;

#else

            int64_t msb = part.frac << (parm->frac_shift + 2);

            int64_t msb = part.frac << 2;

            if ((msb < 0) == status->snan_bit_is_one) {

                part.cls = float_class_snan;

            } else {
@@ -480,6 +481,7 @@ static FloatParts round_canonical(FloatParts p, float_status *s, 
    case float_class_qnan:

    case float_class_snan:

        exp = exp_max;

        frac >>= parm->frac_shift;

        break;



    default:
@@ -503,6 +505,7 @@ static float16 float16_round_pack_canonical(FloatParts p, float_status *s) 
    case float_class_dnan:

        return float16_default_nan(s);

    case float_class_msnan:

        p.frac >>= float16_params.frac_shift;

        return float16_maybe_silence_nan(float16_pack_raw(p), s);

    default:

        p = round_canonical(p, s, &float16_params);
@@ -521,6 +524,7 @@ static float32 float32_round_pack_canonical(FloatParts p, float_status *s) 
    case float_class_dnan:

        return float32_default_nan(s);

    case float_class_msnan:

        p.frac >>= float32_params.frac_shift;

        return float32_maybe_silence_nan(float32_pack_raw(p), s);

    default:

        p = round_canonical(p, s, &float32_params);
@@ -539,6 +543,7 @@ static float64 float64_round_pack_canonical(FloatParts p, float_status *s) 
    case float_class_dnan:

        return float64_default_nan(s);

    case float_class_msnan:

        p.frac >>= float64_params.frac_shift;

        return float64_maybe_silence_nan(float64_pack_raw(p), s);

    default:

        p = round_canonical(p, s, &float64_params);