Re: [PATCH v2 02/28] softfloat: Move int_to_float to softfloat-parts.c.inc

[David Hildenbrand <david@redhat.com>]

On 25.05.21 17:06, Richard Henderson wrote:
> Rename to parts$N_sint_to_float.
> Reimplement int{32,64}_to_float128 with FloatParts128.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   fpu/softfloat.c           | 136 +++++++++++---------------------------
>   fpu/softfloat-parts.c.inc |  32 +++++++++
>   2 files changed, 70 insertions(+), 98 deletions(-)
> 
> diff --git a/fpu/softfloat.c b/fpu/softfloat.c
> index 3181678ea9..6404a2997f 100644
> --- a/fpu/softfloat.c
> +++ b/fpu/softfloat.c
> @@ -849,6 +849,14 @@ static uint64_t parts128_float_to_uint(FloatParts128 *p, FloatRoundMode rmode,
>   #define parts_float_to_uint(P, R, Z, M, S) \
>       PARTS_GENERIC_64_128(float_to_uint, P)(P, R, Z, M, S)
>   
> +static void parts64_sint_to_float(FloatParts64 *p, int64_t a,
> +                                  int scale, float_status *s);
> +static void parts128_sint_to_float(FloatParts128 *p, int64_t a,
> +                                   int scale, float_status *s);
> +
> +#define parts_sint_to_float(P, I, Z, S) \
> +    PARTS_GENERIC_64_128(sint_to_float, P)(P, I, Z, S)
> +
>   /*
>    * Helper functions for softfloat-parts.c.inc, per-size operations.
>    */
> @@ -2940,42 +2948,15 @@ uint64_t bfloat16_to_uint64_round_to_zero(bfloat16 a, float_status *s)
>   }
>   
>   /*
> - * Integer to float conversions
> - *
> - * Returns the result of converting the two's complement integer `a'
> - * to the floating-point format. The conversion is performed according
> - * to the IEC/IEEE Standard for Binary Floating-Point Arithmetic.
> + * Signed integer to floating-point conversions
>    */
>   
> -static FloatParts64 int_to_float(int64_t a, int scale, float_status *status)
> -{
> -    FloatParts64 r = { .sign = false };
> -
> -    if (a == 0) {
> -        r.cls = float_class_zero;
> -    } else {
> -        uint64_t f = a;
> -        int shift;
> -
> -        r.cls = float_class_normal;
> -        if (a < 0) {
> -            f = -f;
> -            r.sign = true;
> -        }
> -        shift = clz64(f);
> -        scale = MIN(MAX(scale, -0x10000), 0x10000);
> -
> -        r.exp = DECOMPOSED_BINARY_POINT - shift + scale;
> -        r.frac = f << shift;
> -    }
> -
> -    return r;
> -}
> -
>   float16 int64_to_float16_scalbn(int64_t a, int scale, float_status *status)
>   {
> -    FloatParts64 pa = int_to_float(a, scale, status);
> -    return float16_round_pack_canonical(&pa, status);
> +    FloatParts64 p;
> +
> +    parts_sint_to_float(&p, a, scale, status);
> +    return float16_round_pack_canonical(&p, status);
>   }
>   
>   float16 int32_to_float16_scalbn(int32_t a, int scale, float_status *status)
> @@ -3010,8 +2991,10 @@ float16 int8_to_float16(int8_t a, float_status *status)
>   
>   float32 int64_to_float32_scalbn(int64_t a, int scale, float_status *status)
>   {
> -    FloatParts64 pa = int_to_float(a, scale, status);
> -    return float32_round_pack_canonical(&pa, status);
> +    FloatParts64 p;
> +
> +    parts64_sint_to_float(&p, a, scale, status);
> +    return float32_round_pack_canonical(&p, status);
>   }
>   
>   float32 int32_to_float32_scalbn(int32_t a, int scale, float_status *status)
> @@ -3041,8 +3024,10 @@ float32 int16_to_float32(int16_t a, float_status *status)
>   
>   float64 int64_to_float64_scalbn(int64_t a, int scale, float_status *status)
>   {
> -    FloatParts64 pa = int_to_float(a, scale, status);
> -    return float64_round_pack_canonical(&pa, status);
> +    FloatParts64 p;
> +
> +    parts_sint_to_float(&p, a, scale, status);
> +    return float64_round_pack_canonical(&p, status);
>   }
>   
>   float64 int32_to_float64_scalbn(int32_t a, int scale, float_status *status)
> @@ -3070,15 +3055,12 @@ float64 int16_to_float64(int16_t a, float_status *status)
>       return int64_to_float64_scalbn(a, 0, status);
>   }
>   
> -/*
> - * Returns the result of converting the two's complement integer `a'
> - * to the bfloat16 format.
> - */
> -
>   bfloat16 int64_to_bfloat16_scalbn(int64_t a, int scale, float_status *status)
>   {
> -    FloatParts64 pa = int_to_float(a, scale, status);
> -    return bfloat16_round_pack_canonical(&pa, status);
> +    FloatParts64 p;
> +
> +    parts_sint_to_float(&p, a, scale, status);
> +    return bfloat16_round_pack_canonical(&p, status);
>   }
>   
>   bfloat16 int32_to_bfloat16_scalbn(int32_t a, int scale, float_status *status)
> @@ -3106,6 +3088,19 @@ bfloat16 int16_to_bfloat16(int16_t a, float_status *status)
>       return int64_to_bfloat16_scalbn(a, 0, status);
>   }
>   
> +float128 int64_to_float128(int64_t a, float_status *status)
> +{
> +    FloatParts128 p;
> +
> +    parts_sint_to_float(&p, a, 0, status);
> +    return float128_round_pack_canonical(&p, status);
> +}
> +
> +float128 int32_to_float128(int32_t a, float_status *status)
> +{
> +    return int64_to_float128(a, status);
> +}
> +
>   /*
>    * Unsigned Integer to float conversions
>    *
> @@ -4956,28 +4951,6 @@ floatx80 int32_to_floatx80(int32_t a, float_status *status)
>   
>   }
>   
> -/*----------------------------------------------------------------------------
> -| Returns the result of converting the 32-bit two's complement integer `a' to
> -| the quadruple-precision floating-point format.  The conversion is performed
> -| according to the IEC/IEEE Standard for Binary Floating-Point Arithmetic.
> -*----------------------------------------------------------------------------*/
> -
> -float128 int32_to_float128(int32_t a, float_status *status)
> -{
> -    bool zSign;
> -    uint32_t absA;
> -    int8_t shiftCount;
> -    uint64_t zSig0;
> -
> -    if ( a == 0 ) return packFloat128( 0, 0, 0, 0 );
> -    zSign = ( a < 0 );
> -    absA = zSign ? - a : a;
> -    shiftCount = clz32(absA) + 17;
> -    zSig0 = absA;
> -    return packFloat128( zSign, 0x402E - shiftCount, zSig0<<shiftCount, 0 );
> -
> -}
> -
>   /*----------------------------------------------------------------------------
>   | Returns the result of converting the 64-bit two's complement integer `a'
>   | to the extended double-precision floating-point format.  The conversion
> @@ -4999,39 +4972,6 @@ floatx80 int64_to_floatx80(int64_t a, float_status *status)
>   
>   }
>   
> -/*----------------------------------------------------------------------------
> -| Returns the result of converting the 64-bit two's complement integer `a' to
> -| the quadruple-precision floating-point format.  The conversion is performed
> -| according to the IEC/IEEE Standard for Binary Floating-Point Arithmetic.
> -*----------------------------------------------------------------------------*/
> -
> -float128 int64_to_float128(int64_t a, float_status *status)
> -{
> -    bool zSign;
> -    uint64_t absA;
> -    int8_t shiftCount;
> -    int32_t zExp;
> -    uint64_t zSig0, zSig1;
> -
> -    if ( a == 0 ) return packFloat128( 0, 0, 0, 0 );
> -    zSign = ( a < 0 );
> -    absA = zSign ? - a : a;
> -    shiftCount = clz64(absA) + 49;
> -    zExp = 0x406E - shiftCount;
> -    if ( 64 <= shiftCount ) {
> -        zSig1 = 0;
> -        zSig0 = absA;
> -        shiftCount -= 64;
> -    }
> -    else {
> -        zSig1 = absA;
> -        zSig0 = 0;
> -    }
> -    shortShift128Left( zSig0, zSig1, shiftCount, &zSig0, &zSig1 );
> -    return packFloat128( zSign, zExp, zSig0, zSig1 );
> -
> -}
> -
>   /*----------------------------------------------------------------------------
>   | Returns the result of converting the 64-bit unsigned integer `a'
>   | to the quadruple-precision floating-point format.  The conversion is performed
> diff --git a/fpu/softfloat-parts.c.inc b/fpu/softfloat-parts.c.inc
> index c6e327547f..8102de1307 100644
> --- a/fpu/softfloat-parts.c.inc
> +++ b/fpu/softfloat-parts.c.inc
> @@ -881,3 +881,35 @@ static uint64_t partsN(float_to_uint)(FloatPartsN *p, FloatRoundMode rmode,
>       float_raise(flags, s);
>       return r;
>   }
> +
> +/*
> + * Integer to float conversions
> + *
> + * Returns the result of converting the two's complement integer `a'
> + * to the floating-point format. The conversion is performed according
> + * to the IEC/IEEE Standard for Binary Floating-Point Arithmetic.
> + */
> +static void partsN(sint_to_float)(FloatPartsN *p, int64_t a,
> +                                  int scale, float_status *s)
> +{
> +    uint64_t f = a;
> +    int shift;
> +
> +    memset(p, 0, sizeof(*p));
> +
> +    if (a == 0) {
> +        p->cls = float_class_zero;
> +        return;
> +    }
> +
> +    p->cls = float_class_normal;
> +    if (a < 0) {
> +        f = -f;
> +        p->sign = true;
> +    }
> +    shift = clz64(f);
> +    scale = MIN(MAX(scale, -0x10000), 0x10000);
> +
> +    p->exp = DECOMPOSED_BINARY_POINT - shift + scale;
> +    p->frac_hi = f << shift;
> +}
> 

LGTM

Reviewed-by: David Hildenbrand <david@redhat.com>

-- 
Thanks,

David / dhildenb