Re: [PATCH v3 32/42] target/arm: Extract HA and HD in aa64_va_parameters
On Fri, 7 Oct 2022 at 17:13, Richard Henderson wrote: > > On 10/7/22 09:11, Peter Maydell wrote: > > On Fri, 7 Oct 2022 at 16:37, Richard Henderson > > wrote: > >> > >> On 10/7/22 02:24, Peter Maydell wrote: > +.ha = ha, > +.hd = ha & hd, > >>> > >>> This is a bitwise operation on two bools, should be && ? > >> > >> Bitwise works fine, but I can use boolean if you like. > >> > >> I'd be surprised (and filing a missed optimization bug) if the compiler > >> treated these two > >> operations differently in this case (simple bool operands with no side > >> effects). > > > > The different treatment I would expect would be that in the '&' > > case it warns you about using a bitwise operation on a boolean :-) > > Oh, well, no compiler should ever do that, because bool implicitly converts > to int for any > arithmetic, just like char. Yeah, but -Wbool-operation is there to catch bugs where the bitwise operation was unintended and the wrong behaviour. -- PMM
Re: [PATCH v3 32/42] target/arm: Extract HA and HD in aa64_va_parameters
On 10/7/22 02:24, Peter Maydell wrote: +.ha = ha, +.hd = ha & hd, This is a bitwise operation on two bools, should be && ? Bitwise works fine, but I can use boolean if you like. I'd be surprised (and filing a missed optimization bug) if the compiler treated these two operations differently in this case (simple bool operands with no side effects). r~
Re: [PATCH v3 32/42] target/arm: Extract HA and HD in aa64_va_parameters
On Fri, 7 Oct 2022 at 16:37, Richard Henderson wrote: > > On 10/7/22 02:24, Peter Maydell wrote: > >> +.ha = ha, > >> +.hd = ha & hd, > > > > This is a bitwise operation on two bools, should be && ? > > Bitwise works fine, but I can use boolean if you like. > > I'd be surprised (and filing a missed optimization bug) if the compiler > treated these two > operations differently in this case (simple bool operands with no side > effects). The different treatment I would expect would be that in the '&' case it warns you about using a bitwise operation on a boolean :-) -- PMM
Re: [PATCH v3 32/42] target/arm: Extract HA and HD in aa64_va_parameters
On 10/7/22 09:11, Peter Maydell wrote: On Fri, 7 Oct 2022 at 16:37, Richard Henderson wrote: On 10/7/22 02:24, Peter Maydell wrote: +.ha = ha, +.hd = ha & hd, This is a bitwise operation on two bools, should be && ? Bitwise works fine, but I can use boolean if you like. I'd be surprised (and filing a missed optimization bug) if the compiler treated these two operations differently in this case (simple bool operands with no side effects). The different treatment I would expect would be that in the '&' case it warns you about using a bitwise operation on a boolean :-) Oh, well, no compiler should ever do that, because bool implicitly converts to int for any arithmetic, just like char. r~
Re: [PATCH v3 32/42] target/arm: Extract HA and HD in aa64_va_parameters
On Sat, 1 Oct 2022 at 17:42, Richard Henderson
wrote:
>
> Signed-off-by: Richard Henderson
> ---
> target/arm/internals.h | 2 ++
> target/arm/helper.c| 8 +++-
> 2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/target/arm/internals.h b/target/arm/internals.h
> index a50189e2e4..e95b6b1b8f 100644
> --- a/target/arm/internals.h
> +++ b/target/arm/internals.h
> @@ -1014,6 +1014,8 @@ typedef struct ARMVAParameters {
> bool using64k : 1;
> bool tsz_oob: 1; /* tsz has been clamped to legal range */
> bool ds : 1;
> +bool ha : 1;
> +bool hd : 1;
> } ARMVAParameters;
>
> ARMVAParameters aa64_va_parameters(CPUARMState *env, uint64_t va,
> diff --git a/target/arm/helper.c b/target/arm/helper.c
> index 19a03eb200..70ae3816b9 100644
> --- a/target/arm/helper.c
> +++ b/target/arm/helper.c
> @@ -10280,7 +10280,7 @@ ARMVAParameters aa64_va_parameters(CPUARMState *env,
> uint64_t va,
> ARMMMUIdx mmu_idx, bool data)
> {
> uint64_t tcr = regime_tcr(env, mmu_idx);
> -bool epd, hpd, using16k, using64k, tsz_oob, ds;
> +bool epd, hpd, using16k, using64k, tsz_oob, ds, ha, hd;
> int select, tsz, tbi, max_tsz, min_tsz, ps, sh;
> ARMCPU *cpu = env_archcpu(env);
>
> @@ -10298,6 +10298,8 @@ ARMVAParameters aa64_va_parameters(CPUARMState *env,
> uint64_t va,
> epd = false;
> sh = extract32(tcr, 12, 2);
> ps = extract32(tcr, 16, 3);
> +ha = extract32(tcr, 21, 1) && cpu_isar_feature(aa64_hafs, cpu);
> +hd = extract32(tcr, 22, 1) && cpu_isar_feature(aa64_hdbs, cpu);
> ds = extract64(tcr, 32, 1);
> } else {
> /*
> @@ -10322,6 +10324,8 @@ ARMVAParameters aa64_va_parameters(CPUARMState *env,
> uint64_t va,
> hpd = extract64(tcr, 42, 1);
> }
> ps = extract64(tcr, 32, 3);
> +ha = extract64(tcr, 39, 1) && cpu_isar_feature(aa64_hafs, cpu);
> +hd = extract64(tcr, 40, 1) && cpu_isar_feature(aa64_hdbs, cpu);
> ds = extract64(tcr, 59, 1);
> }
>
> @@ -10393,6 +10397,8 @@ ARMVAParameters aa64_va_parameters(CPUARMState *env,
> uint64_t va,
> .using64k = using64k,
> .tsz_oob = tsz_oob,
> .ds = ds,
> +.ha = ha,
> +.hd = ha & hd,
This is a bitwise operation on two bools, should be && ?
Otherwise
Reviewed-by: Peter Maydell
thanks
-- PMM
