| Message ID | 20180514221219.7091-9-richard.henderson@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | softfloat patch roundup | expand |
Richard Henderson <richard.henderson@linaro.org> writes: > With a canonical representation of NaNs, we can silence an SNaN > immediately rather than delay until the final format is known. > > Reviewed-by: Peter Maydell <peter.maydell@linaro.org> > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> > --- > fpu/softfloat-specialize.h | 23 ++++++++++++++++++++++ > fpu/softfloat.c | 40 ++++++++++---------------------------- > 2 files changed, 33 insertions(+), 30 deletions(-) > > diff --git a/fpu/softfloat-specialize.h b/fpu/softfloat-specialize.h > index 0d3d81a52b..571d1df378 100644 > --- a/fpu/softfloat-specialize.h > +++ b/fpu/softfloat-specialize.h > @@ -138,6 +138,29 @@ static FloatParts parts_default_nan(float_status *status) > }; > } > > +/*---------------------------------------------------------------------------- > +| Returns a quiet NaN from a signalling NaN for the deconstructed > +| floating-point parts. > +*----------------------------------------------------------------------------*/ > + > +static FloatParts parts_silence_nan(FloatParts a, float_status *status) > +{ > +#ifdef NO_SIGNALING_NANS > + g_assert_not_reached(); > +#elif defined(TARGET_HPPA) > + a.frac &= ~(1ULL << (DECOMPOSED_BINARY_POINT - 1)); > + a.frac |= 1ULL << (DECOMPOSED_BINARY_POINT - 2); > +#else > + if (status->snan_bit_is_one) { > + return parts_default_nan(status); > + } else { > + a.frac |= 1ULL << (DECOMPOSED_BINARY_POINT - 1); > + } > +#endif > + a.cls = float_class_qnan; > + return a; > +} > + > /*---------------------------------------------------------------------------- > | The pattern for a default generated half-precision NaN. > *----------------------------------------------------------------------------*/ > diff --git a/fpu/softfloat.c b/fpu/softfloat.c > index 51780b718f..41253c6749 100644 > --- a/fpu/softfloat.c > +++ b/fpu/softfloat.c > @@ -188,7 +188,6 @@ typedef enum __attribute__ ((__packed__)) { > float_class_inf, > float_class_qnan, /* all NaNs from here */ > float_class_snan, > - float_class_msnan, /* maybe silenced */ > } FloatClass; > > /* > @@ -492,14 +491,7 @@ static FloatParts float16_unpack_canonical(float16 f, float_status *s) > > static float16 float16_round_pack_canonical(FloatParts p, float_status *s) > { > - switch (p.cls) { > - 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); > - return float16_pack_raw(p); > - } > + return float16_pack_raw(round_canonical(p, s, &float16_params)); > } > > static FloatParts float32_unpack_canonical(float32 f, float_status *s) > @@ -509,14 +501,7 @@ static FloatParts float32_unpack_canonical(float32 f, float_status *s) > > static float32 float32_round_pack_canonical(FloatParts p, float_status *s) > { > - switch (p.cls) { > - 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); > - return float32_pack_raw(p); > - } > + return float32_pack_raw(round_canonical(p, s, &float32_params)); > } > > static FloatParts float64_unpack_canonical(float64 f, float_status *s) > @@ -526,14 +511,7 @@ static FloatParts float64_unpack_canonical(float64 f, float_status *s) > > static float64 float64_round_pack_canonical(FloatParts p, float_status *s) > { > - switch (p.cls) { > - 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); > - return float64_pack_raw(p); > - } > + return float64_pack_raw(round_canonical(p, s, &float64_params)); > } > > /* Simple helpers for checking if what NaN we have */ > @@ -555,7 +533,7 @@ static FloatParts return_nan(FloatParts a, float_status *s) > switch (a.cls) { > case float_class_snan: > s->float_exception_flags |= float_flag_invalid; > - a.cls = float_class_msnan; > + a = parts_silence_nan(a, s); > /* fall through */ > case float_class_qnan: > if (s->default_nan_mode) { > @@ -584,7 +562,9 @@ static FloatParts pick_nan(FloatParts a, FloatParts b, float_status *s) > (a.frac == b.frac && a.sign < b.sign))) { > a = b; > } > - a.cls = float_class_msnan; > + if (is_snan(a.cls)) { > + return parts_silence_nan(a, s); > + } > } > return a; > } > @@ -624,8 +604,10 @@ static FloatParts pick_nan_muladd(FloatParts a, FloatParts b, FloatParts c, > default: > g_assert_not_reached(); > } > - a.cls = float_class_msnan; > > + if (is_snan(a.cls)) { > + return parts_silence_nan(a, s); > + } > return a; > } > > @@ -1334,7 +1316,6 @@ static int64_t round_to_int_and_pack(FloatParts in, int rmode, > switch (p.cls) { > case float_class_snan: > case float_class_qnan: > - case float_class_msnan: > s->float_exception_flags = orig_flags | float_flag_invalid; > return max; > case float_class_inf: > @@ -1425,7 +1406,6 @@ static uint64_t round_to_uint_and_pack(FloatParts in, int rmode, uint64_t max, > switch (p.cls) { > case float_class_snan: > case float_class_qnan: > - case float_class_msnan: > s->float_exception_flags = orig_flags | float_flag_invalid; > return max; > case float_class_inf: -- Alex Bennée
diff --git a/fpu/softfloat-specialize.h b/fpu/softfloat-specialize.h index 0d3d81a52b..571d1df378 100644 --- a/fpu/softfloat-specialize.h +++ b/fpu/softfloat-specialize.h @@ -138,6 +138,29 @@ static FloatParts parts_default_nan(float_status *status) }; } +/*---------------------------------------------------------------------------- +| Returns a quiet NaN from a signalling NaN for the deconstructed +| floating-point parts. +*----------------------------------------------------------------------------*/ + +static FloatParts parts_silence_nan(FloatParts a, float_status *status) +{ +#ifdef NO_SIGNALING_NANS + g_assert_not_reached(); +#elif defined(TARGET_HPPA) + a.frac &= ~(1ULL << (DECOMPOSED_BINARY_POINT - 1)); + a.frac |= 1ULL << (DECOMPOSED_BINARY_POINT - 2); +#else + if (status->snan_bit_is_one) { + return parts_default_nan(status); + } else { + a.frac |= 1ULL << (DECOMPOSED_BINARY_POINT - 1); + } +#endif + a.cls = float_class_qnan; + return a; +} + /*---------------------------------------------------------------------------- | The pattern for a default generated half-precision NaN. *----------------------------------------------------------------------------*/ diff --git a/fpu/softfloat.c b/fpu/softfloat.c index 51780b718f..41253c6749 100644 --- a/fpu/softfloat.c +++ b/fpu/softfloat.c @@ -188,7 +188,6 @@ typedef enum __attribute__ ((__packed__)) { float_class_inf, float_class_qnan, /* all NaNs from here */ float_class_snan, - float_class_msnan, /* maybe silenced */ } FloatClass; /* @@ -492,14 +491,7 @@ static FloatParts float16_unpack_canonical(float16 f, float_status *s) static float16 float16_round_pack_canonical(FloatParts p, float_status *s) { - switch (p.cls) { - 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); - return float16_pack_raw(p); - } + return float16_pack_raw(round_canonical(p, s, &float16_params)); } static FloatParts float32_unpack_canonical(float32 f, float_status *s) @@ -509,14 +501,7 @@ static FloatParts float32_unpack_canonical(float32 f, float_status *s) static float32 float32_round_pack_canonical(FloatParts p, float_status *s) { - switch (p.cls) { - 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); - return float32_pack_raw(p); - } + return float32_pack_raw(round_canonical(p, s, &float32_params)); } static FloatParts float64_unpack_canonical(float64 f, float_status *s) @@ -526,14 +511,7 @@ static FloatParts float64_unpack_canonical(float64 f, float_status *s) static float64 float64_round_pack_canonical(FloatParts p, float_status *s) { - switch (p.cls) { - 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); - return float64_pack_raw(p); - } + return float64_pack_raw(round_canonical(p, s, &float64_params)); } /* Simple helpers for checking if what NaN we have */ @@ -555,7 +533,7 @@ static FloatParts return_nan(FloatParts a, float_status *s) switch (a.cls) { case float_class_snan: s->float_exception_flags |= float_flag_invalid; - a.cls = float_class_msnan; + a = parts_silence_nan(a, s); /* fall through */ case float_class_qnan: if (s->default_nan_mode) { @@ -584,7 +562,9 @@ static FloatParts pick_nan(FloatParts a, FloatParts b, float_status *s) (a.frac == b.frac && a.sign < b.sign))) { a = b; } - a.cls = float_class_msnan; + if (is_snan(a.cls)) { + return parts_silence_nan(a, s); + } } return a; } @@ -624,8 +604,10 @@ static FloatParts pick_nan_muladd(FloatParts a, FloatParts b, FloatParts c, default: g_assert_not_reached(); } - a.cls = float_class_msnan; + if (is_snan(a.cls)) { + return parts_silence_nan(a, s); + } return a; } @@ -1334,7 +1316,6 @@ static int64_t round_to_int_and_pack(FloatParts in, int rmode, switch (p.cls) { case float_class_snan: case float_class_qnan: - case float_class_msnan: s->float_exception_flags = orig_flags | float_flag_invalid; return max; case float_class_inf: @@ -1425,7 +1406,6 @@ static uint64_t round_to_uint_and_pack(FloatParts in, int rmode, uint64_t max, switch (p.cls) { case float_class_snan: case float_class_qnan: - case float_class_msnan: s->float_exception_flags = orig_flags | float_flag_invalid; return max; case float_class_inf: