| Message ID | 20180514221219.7091-8-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| State | Superseded |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 return the > default nan directly rather than delay the expansion until > the final format is known. > > Note one case where we uselessly assigned to a.sign, which was > overwritten/ignored later when expanding float_class_dnan. > > 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 | 37 +++++++++++++++++++++++++++++++++++++ > fpu/softfloat.c | 38 +++++++++++--------------------------- > 2 files changed, 48 insertions(+), 27 deletions(-) > > diff --git a/fpu/softfloat-specialize.h b/fpu/softfloat-specialize.h > index 515cb12cfa..0d3d81a52b 100644 > --- a/fpu/softfloat-specialize.h > +++ b/fpu/softfloat-specialize.h > @@ -101,6 +101,43 @@ static bool parts_is_snan_frac(uint64_t frac, float_status *status) > #endif > } > > +/*---------------------------------------------------------------------------- > +| The pattern for a default generated deconstructed floating-point NaN. > +*----------------------------------------------------------------------------*/ > + > +static FloatParts parts_default_nan(float_status *status) > +{ > + bool sign = 0; > + uint64_t frac; > + > +#if defined(TARGET_SPARC) || defined(TARGET_M68K) > + frac = (1ULL << DECOMPOSED_BINARY_POINT) - 1; > +#elif defined(TARGET_PPC) || defined(TARGET_ARM) || defined(TARGET_ALPHA) || \ > + defined(TARGET_S390X) || defined(TARGET_RISCV) > + frac = 1ULL << (DECOMPOSED_BINARY_POINT - 1); > +#elif defined(TARGET_HPPA) > + frac = 1ULL << (DECOMPOSED_BINARY_POINT - 2); > +#else > + if (status->snan_bit_is_one) { > + frac = (1ULL << (DECOMPOSED_BINARY_POINT - 1)) - 1; > + } else { > +#if defined(TARGET_MIPS) > + frac = 1ULL << (DECOMPOSED_BINARY_POINT - 1); > +#else > + frac = 1ULL << (DECOMPOSED_BINARY_POINT - 1); > + sign = 1; > +#endif > + } > +#endif > + > + return (FloatParts) { > + .cls = float_class_qnan, > + .sign = sign, > + .exp = INT_MAX, > + .frac = frac > + }; > +} > + > /*---------------------------------------------------------------------------- > | The pattern for a default generated half-precision NaN. > *----------------------------------------------------------------------------*/ > diff --git a/fpu/softfloat.c b/fpu/softfloat.c > index 19f40d6932..51780b718f 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_dnan, > float_class_msnan, /* maybe silenced */ > } FloatClass; > > @@ -494,8 +493,6 @@ 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_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); > @@ -513,8 +510,6 @@ 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_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); > @@ -532,8 +527,6 @@ 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_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); > @@ -566,7 +559,7 @@ static FloatParts return_nan(FloatParts a, float_status *s) > /* fall through */ > case float_class_qnan: > if (s->default_nan_mode) { > - a.cls = float_class_dnan; > + return parts_default_nan(s); > } > break; > > @@ -583,7 +576,7 @@ static FloatParts pick_nan(FloatParts a, FloatParts b, float_status *s) > } > > if (s->default_nan_mode) { > - a.cls = float_class_dnan; > + return parts_default_nan(s); > } else { > if (pickNaN(is_qnan(a.cls), is_snan(a.cls), > is_qnan(b.cls), is_snan(b.cls), > @@ -614,8 +607,7 @@ static FloatParts pick_nan_muladd(FloatParts a, FloatParts b, FloatParts c, > /* Note that this check is after pickNaNMulAdd so that function > * has an opportunity to set the Invalid flag. > */ > - a.cls = float_class_dnan; > - return a; > + which = 3; > } > > switch (which) { > @@ -628,8 +620,7 @@ static FloatParts pick_nan_muladd(FloatParts a, FloatParts b, FloatParts c, > a = c; > break; > case 3: > - a.cls = float_class_dnan; > - return a; > + return parts_default_nan(s); > default: > g_assert_not_reached(); > } > @@ -682,7 +673,7 @@ static FloatParts addsub_floats(FloatParts a, FloatParts b, bool subtract, > if (a.cls == float_class_inf) { > if (b.cls == float_class_inf) { > float_raise(float_flag_invalid, s); > - a.cls = float_class_dnan; > + return parts_default_nan(s); > } > return a; > } > @@ -828,9 +819,7 @@ static FloatParts mul_floats(FloatParts a, FloatParts b, float_status *s) > if ((a.cls == float_class_inf && b.cls == float_class_zero) || > (a.cls == float_class_zero && b.cls == float_class_inf)) { > s->float_exception_flags |= float_flag_invalid; > - a.cls = float_class_dnan; > - a.sign = sign; > - return a; > + return parts_default_nan(s); > } > /* Multiply by 0 or Inf */ > if (a.cls == float_class_inf || a.cls == float_class_zero) { > @@ -908,8 +897,7 @@ static FloatParts muladd_floats(FloatParts a, FloatParts b, FloatParts c, > > if (inf_zero) { > s->float_exception_flags |= float_flag_invalid; > - a.cls = float_class_dnan; > - return a; > + return parts_default_nan(s); > } > > if (flags & float_muladd_negate_c) { > @@ -933,12 +921,12 @@ static FloatParts muladd_floats(FloatParts a, FloatParts b, FloatParts c, > if (c.cls == float_class_inf) { > if (p_class == float_class_inf && p_sign != c.sign) { > s->float_exception_flags |= float_flag_invalid; > - a.cls = float_class_dnan; > + return parts_default_nan(s); > } else { > a.cls = float_class_inf; > a.sign = c.sign ^ sign_flip; > + return a; > } > - return a; > } > > if (p_class == float_class_inf) { > @@ -1148,8 +1136,7 @@ static FloatParts div_floats(FloatParts a, FloatParts b, float_status *s) > && > (a.cls == float_class_inf || a.cls == float_class_zero)) { > s->float_exception_flags |= float_flag_invalid; > - a.cls = float_class_dnan; > - return a; > + return parts_default_nan(s); > } > /* Inf / x or 0 / x */ > if (a.cls == float_class_inf || a.cls == float_class_zero) { > @@ -1347,7 +1334,6 @@ 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_dnan: > case float_class_msnan: > s->float_exception_flags = orig_flags | float_flag_invalid; > return max; > @@ -1439,7 +1425,6 @@ 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_dnan: > case float_class_msnan: > s->float_exception_flags = orig_flags | float_flag_invalid; > return max; > @@ -1940,8 +1925,7 @@ static FloatParts sqrt_float(FloatParts a, float_status *s, const FloatFmt *p) > } > if (a.sign) { > s->float_exception_flags |= float_flag_invalid; > - a.cls = float_class_dnan; > - return a; > + return parts_default_nan(s); > } > if (a.cls == float_class_inf) { > return a; /* sqrt(+inf) = +inf */ -- Alex Bennée
diff --git a/fpu/softfloat-specialize.h b/fpu/softfloat-specialize.h index 515cb12cfa..0d3d81a52b 100644 --- a/fpu/softfloat-specialize.h +++ b/fpu/softfloat-specialize.h @@ -101,6 +101,43 @@ static bool parts_is_snan_frac(uint64_t frac, float_status *status) #endif } +/*---------------------------------------------------------------------------- +| The pattern for a default generated deconstructed floating-point NaN. +*----------------------------------------------------------------------------*/ + +static FloatParts parts_default_nan(float_status *status) +{ + bool sign = 0; + uint64_t frac; + +#if defined(TARGET_SPARC) || defined(TARGET_M68K) + frac = (1ULL << DECOMPOSED_BINARY_POINT) - 1; +#elif defined(TARGET_PPC) || defined(TARGET_ARM) || defined(TARGET_ALPHA) || \ + defined(TARGET_S390X) || defined(TARGET_RISCV) + frac = 1ULL << (DECOMPOSED_BINARY_POINT - 1); +#elif defined(TARGET_HPPA) + frac = 1ULL << (DECOMPOSED_BINARY_POINT - 2); +#else + if (status->snan_bit_is_one) { + frac = (1ULL << (DECOMPOSED_BINARY_POINT - 1)) - 1; + } else { +#if defined(TARGET_MIPS) + frac = 1ULL << (DECOMPOSED_BINARY_POINT - 1); +#else + frac = 1ULL << (DECOMPOSED_BINARY_POINT - 1); + sign = 1; +#endif + } +#endif + + return (FloatParts) { + .cls = float_class_qnan, + .sign = sign, + .exp = INT_MAX, + .frac = frac + }; +} + /*---------------------------------------------------------------------------- | The pattern for a default generated half-precision NaN. *----------------------------------------------------------------------------*/ diff --git a/fpu/softfloat.c b/fpu/softfloat.c index 19f40d6932..51780b718f 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_dnan, float_class_msnan, /* maybe silenced */ } FloatClass; @@ -494,8 +493,6 @@ 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_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); @@ -513,8 +510,6 @@ 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_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); @@ -532,8 +527,6 @@ 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_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); @@ -566,7 +559,7 @@ static FloatParts return_nan(FloatParts a, float_status *s) /* fall through */ case float_class_qnan: if (s->default_nan_mode) { - a.cls = float_class_dnan; + return parts_default_nan(s); } break; @@ -583,7 +576,7 @@ static FloatParts pick_nan(FloatParts a, FloatParts b, float_status *s) } if (s->default_nan_mode) { - a.cls = float_class_dnan; + return parts_default_nan(s); } else { if (pickNaN(is_qnan(a.cls), is_snan(a.cls), is_qnan(b.cls), is_snan(b.cls), @@ -614,8 +607,7 @@ static FloatParts pick_nan_muladd(FloatParts a, FloatParts b, FloatParts c, /* Note that this check is after pickNaNMulAdd so that function * has an opportunity to set the Invalid flag. */ - a.cls = float_class_dnan; - return a; + which = 3; } switch (which) { @@ -628,8 +620,7 @@ static FloatParts pick_nan_muladd(FloatParts a, FloatParts b, FloatParts c, a = c; break; case 3: - a.cls = float_class_dnan; - return a; + return parts_default_nan(s); default: g_assert_not_reached(); } @@ -682,7 +673,7 @@ static FloatParts addsub_floats(FloatParts a, FloatParts b, bool subtract, if (a.cls == float_class_inf) { if (b.cls == float_class_inf) { float_raise(float_flag_invalid, s); - a.cls = float_class_dnan; + return parts_default_nan(s); } return a; } @@ -828,9 +819,7 @@ static FloatParts mul_floats(FloatParts a, FloatParts b, float_status *s) if ((a.cls == float_class_inf && b.cls == float_class_zero) || (a.cls == float_class_zero && b.cls == float_class_inf)) { s->float_exception_flags |= float_flag_invalid; - a.cls = float_class_dnan; - a.sign = sign; - return a; + return parts_default_nan(s); } /* Multiply by 0 or Inf */ if (a.cls == float_class_inf || a.cls == float_class_zero) { @@ -908,8 +897,7 @@ static FloatParts muladd_floats(FloatParts a, FloatParts b, FloatParts c, if (inf_zero) { s->float_exception_flags |= float_flag_invalid; - a.cls = float_class_dnan; - return a; + return parts_default_nan(s); } if (flags & float_muladd_negate_c) { @@ -933,12 +921,12 @@ static FloatParts muladd_floats(FloatParts a, FloatParts b, FloatParts c, if (c.cls == float_class_inf) { if (p_class == float_class_inf && p_sign != c.sign) { s->float_exception_flags |= float_flag_invalid; - a.cls = float_class_dnan; + return parts_default_nan(s); } else { a.cls = float_class_inf; a.sign = c.sign ^ sign_flip; + return a; } - return a; } if (p_class == float_class_inf) { @@ -1148,8 +1136,7 @@ static FloatParts div_floats(FloatParts a, FloatParts b, float_status *s) && (a.cls == float_class_inf || a.cls == float_class_zero)) { s->float_exception_flags |= float_flag_invalid; - a.cls = float_class_dnan; - return a; + return parts_default_nan(s); } /* Inf / x or 0 / x */ if (a.cls == float_class_inf || a.cls == float_class_zero) { @@ -1347,7 +1334,6 @@ 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_dnan: case float_class_msnan: s->float_exception_flags = orig_flags | float_flag_invalid; return max; @@ -1439,7 +1425,6 @@ 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_dnan: case float_class_msnan: s->float_exception_flags = orig_flags | float_flag_invalid; return max; @@ -1940,8 +1925,7 @@ static FloatParts sqrt_float(FloatParts a, float_status *s, const FloatFmt *p) } if (a.sign) { s->float_exception_flags |= float_flag_invalid; - a.cls = float_class_dnan; - return a; + return parts_default_nan(s); } if (a.cls == float_class_inf) { return a; /* sqrt(+inf) = +inf */