Re: [PATCH 05/11] target/i386: Use float_flag_inorm_denormal

[Richard Henderson]

Ping.  Cc paolo, ed.

This is the last unreviewed patch in this series, and the one that sparked the work in the 
first place.

r~

On 5/26/21 9:13 PM, Richard Henderson wrote:
> The FSR and MXCSR DE flags have the semantics of the new flag.
> We get to remove a big fixme in update_mxcsr_from_sse_status
> vs float_flag_iflush_denormal.
>
> Reported-by: Michael Morrell <mmorrell@tachyum.com>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   target/i386/tcg/fpu_helper.c | 18 ++++++------------
>   1 file changed, 6 insertions(+), 12 deletions(-)
>
> diff --git a/target/i386/tcg/fpu_helper.c b/target/i386/tcg/fpu_helper.c
> index c9779a9fe0..edc550de55 100644
> --- a/target/i386/tcg/fpu_helper.c
> +++ b/target/i386/tcg/fpu_helper.c
> @@ -148,7 +148,7 @@ static void merge_exception_flags(CPUX86State *env, uint8_t 
> old_flags)
>                          (new_flags & float_flag_overflow ? FPUS_OE : 0) |
>                          (new_flags & float_flag_underflow ? FPUS_UE : 0) |
>                          (new_flags & float_flag_inexact ? FPUS_PE : 0) |
> -                       (new_flags & float_flag_iflush_denormal ? FPUS_DE : 
> 0)));
> +                       (new_flags & float_flag_inorm_denormal ? FPUS_DE : 0)));
>   }
>   
>   static inline floatx80 helper_fdiv(CPUX86State *env, floatx80 a, floatx80 b)
> @@ -1742,7 +1742,7 @@ void helper_fxtract(CPUX86State *env)
>               int shift = clz64(temp.l.lower);
>               temp.l.lower <<= shift;
>               expdif = 1 - EXPBIAS - shift;
> -            float_raise(float_flag_iflush_denormal, &env->fp_status);
> +            float_raise(float_flag_inorm_denormal, &env->fp_status);
>           } else {
>               expdif = EXPD(temp) - EXPBIAS;
>           }
> @@ -2976,7 +2976,8 @@ void update_mxcsr_status(CPUX86State *env)
>                                 (mxcsr & FPUS_ZE ? float_flag_divbyzero : 0) |
>                                 (mxcsr & FPUS_OE ? float_flag_overflow : 0) |
>                                 (mxcsr & FPUS_UE ? float_flag_underflow : 0) |
> -                              (mxcsr & FPUS_PE ? float_flag_inexact : 0),
> +                              (mxcsr & FPUS_PE ? float_flag_inexact : 0) |
> +                              (mxcsr & FPUS_DE ? float_flag_inorm_denormal : 
> 0),
>                                 &env->sse_status);
>   
>       /* set denormals are zero */
> @@ -2989,20 +2990,13 @@ void update_mxcsr_status(CPUX86State *env)
>   void update_mxcsr_from_sse_status(CPUX86State *env)
>   {
>       uint8_t flags = get_float_exception_flags(&env->sse_status);
> -    /*
> -     * The MXCSR denormal flag has opposite semantics to
> -     * float_flag_iflush_denormal (the softfloat code sets that flag
> -     * only when flushing input denormals to zero, but SSE sets it
> -     * only when not flushing them to zero), so is not converted
> -     * here.
> -     */
>       env->mxcsr |= ((flags & float_flag_invalid ? FPUS_IE : 0) |
>                      (flags & float_flag_divbyzero ? FPUS_ZE : 0) |
>                      (flags & float_flag_overflow ? FPUS_OE : 0) |
>                      (flags & float_flag_underflow ? FPUS_UE : 0) |
>                      (flags & float_flag_inexact ? FPUS_PE : 0) |
> -                   (flags & float_flag_oflush_denormal ? FPUS_UE | FPUS_PE :
> -                    0));
> +                   (flags & float_flag_inorm_denormal ? FPUS_DE : 0) |
> +                   (flags & float_flag_oflush_denormal ? FPUS_UE | FPUS_PE : 
> 0));
>   }
>   
>   void helper_update_mxcsr(CPUX86State *env)