Re: [Qemu-devel] [PATCH v3 04/13] fpu: use min/max values from stdint.h for integral overflow

[Aleksandar Markovic]

13.08.2019. 14.52, "Alex Bennée" <address@hidden> је написао/ла:
>
> Remove some more use of LIT64 while making the meaning more clear. We
> also avoid the need of casts as the results by definition fit into the
> return type.
>
> Signed-off-by: Alex Bennée <address@hidden>
> ---
>  fpu/softfloat.c | 30 ++++++++++++++----------------
>  1 file changed, 14 insertions(+), 16 deletions(-)
>
> diff --git a/fpu/softfloat.c b/fpu/softfloat.c
> index 9e57b7b5933..a1e1e9a8559 100644
> --- a/fpu/softfloat.c
> +++ b/fpu/softfloat.c
> @@ -3444,9 +3444,7 @@ static int64_t roundAndPackInt64(flag zSign,
uint64_t absZ0, uint64_t absZ1,
>      if ( z && ( ( z < 0 ) ^ zSign ) ) {
>   overflow:
>          float_raise(float_flag_invalid, status);
> -        return
> -              zSign ? (int64_t) LIT64( 0x8000000000000000 )
> -            : LIT64( 0x7FFFFFFFFFFFFFFF );
> +        return zSign ? INT64_MIN : INT64_MAX;
>      }

In function roundAndPavkInt32 tgere is a following segment:

    if ( ( absZ>>32 ) || ( z && ( ( z < 0 ) ^ zSign ) ) ) {
        float_raise(float_flag_invalid, status);
        return zSign ? (int32_t) 0x80000000 : 0x7FFFFFFF;
    }

Perhaps replace these constants with INT32_MIN, INT32_MAX, for similar
reasons, in the same or a separate patch?

Aleksandar


>      if (absZ1) {
>          status->float_exception_flags |= float_flag_inexact;
> @@ -3497,7 +3495,7 @@ static int64_t roundAndPackUint64(flag zSign,
uint64_t absZ0,
>          ++absZ0;
>          if (absZ0 == 0) {
>              float_raise(float_flag_invalid, status);
> -            return LIT64(0xFFFFFFFFFFFFFFFF);
> +            return UINT64_MAX;
>          }
>          absZ0 &= ~(((uint64_t)(absZ1<<1) == 0) & roundNearestEven);
>      }
> @@ -5518,9 +5516,9 @@ int64_t floatx80_to_int64(floatx80 a, float_status
*status)
>          if ( shiftCount ) {
>              float_raise(float_flag_invalid, status);
>              if (!aSign || floatx80_is_any_nan(a)) {
> -                return LIT64( 0x7FFFFFFFFFFFFFFF );
> +                return INT64_MAX;
>              }
> -            return (int64_t) LIT64( 0x8000000000000000 );
> +            return INT64_MIN;
>          }
>          aSigExtra = 0;
>      }
> @@ -5561,10 +5559,10 @@ int64_t floatx80_to_int64_round_to_zero(floatx80
a, float_status *status)
>          if ( ( a.high != 0xC03E ) || aSig ) {
>              float_raise(float_flag_invalid, status);
>              if ( ! aSign || ( ( aExp == 0x7FFF ) && aSig ) ) {
> -                return LIT64( 0x7FFFFFFFFFFFFFFF );
> +                return INT64_MAX;
>              }
>          }
> -        return (int64_t) LIT64( 0x8000000000000000 );
> +        return INT64_MIN;
>      }
>      else if ( aExp < 0x3FFF ) {
>          if (aExp | aSig) {
> @@ -6623,7 +6621,7 @@ int32_t float128_to_int32_round_to_zero(float128 a,
float_status *status)
>      if ( ( z < 0 ) ^ aSign ) {
>   invalid:
>          float_raise(float_flag_invalid, status);
> -        return aSign ? (int32_t) 0x80000000 : 0x7FFFFFFF;
> +        return aSign ? INT32_MIN : INT32_MAX;
>      }
>      if ( ( aSig0<<shiftCount ) != savedASig ) {
>          status->float_exception_flags |= float_flag_inexact;
> @@ -6662,9 +6660,9 @@ int64_t float128_to_int64(float128 a, float_status
*status)
>                        && ( aSig1 || ( aSig0 != LIT64( 0x0001000000000000
) ) )
>                      )
>                 ) {
> -                return LIT64( 0x7FFFFFFFFFFFFFFF );
> +                return INT64_MAX;
>              }
> -            return (int64_t) LIT64( 0x8000000000000000 );
> +            return INT64_MIN;
>          }
>          shortShift128Left( aSig0, aSig1, - shiftCount, &aSig0, &aSig1 );
>      }
> @@ -6710,10 +6708,10 @@ int64_t float128_to_int64_round_to_zero(float128
a, float_status *status)
>              else {
>                  float_raise(float_flag_invalid, status);
>                  if ( ! aSign || ( ( aExp == 0x7FFF ) && ( aSig0 | aSig1
) ) ) {
> -                    return LIT64( 0x7FFFFFFFFFFFFFFF );
> +                    return INT64_MAX;
>                  }
>              }
> -            return (int64_t) LIT64( 0x8000000000000000 );
> +            return INT64_MIN;
>          }
>          z = ( aSig0<<shiftCount ) | ( aSig1>>( ( - shiftCount ) & 63 ) );
>          if ( (uint64_t) ( aSig1<<shiftCount ) ) {
> @@ -6764,19 +6762,19 @@ uint64_t float128_to_uint64(float128 a,
float_status *status)
>      if (aSign && (aExp > 0x3FFE)) {
>          float_raise(float_flag_invalid, status);
>          if (float128_is_any_nan(a)) {
> -            return LIT64(0xFFFFFFFFFFFFFFFF);
> +            return UINT64_MAX;
>          } else {
>              return 0;
>          }
>      }
>      if (aExp) {
> -        aSig0 |= LIT64(0x0001000000000000);
> +        aSig0 |= UINT64_C(0x0001000000000000);
>      }
>      shiftCount = 0x402F - aExp;
>      if (shiftCount <= 0) {
>          if (0x403E < aExp) {
>              float_raise(float_flag_invalid, status);
> -            return LIT64(0xFFFFFFFFFFFFFFFF);
> +            return UINT64_MAX;
>          }
>          shortShift128Left(aSig0, aSig1, -shiftCount, &aSig0, &aSig1);
>      } else {
> --
> 2.20.1
>
>