Re: [Minios-devel] [UNIKRAFT PATCH v6 6/7] arch/arm64: Implement bitops for arm64

["Justin He (Arm Technology China)" <Justin.He@xxxxxxx>]

Hi Santiago
Thanks for your review 

--
Cheers,
Justin (Jia He)



> -----Original Message-----
> From: Santiago Pagani <Santiago.Pagani@xxxxxxxxx>
> Sent: Tuesday, October 22, 2019 4:40 PM
> To: Justin He (Arm Technology China) <Justin.He@xxxxxxx>; minios-
> devel@xxxxxxxxxxxxxxxxxxxx
> Cc: Simon Kuenzer <simon.kuenzer@xxxxxxxxx>; Sharan Santhanam
> <Sharan.Santhanam@xxxxxxxxx>; Felipe Huici <Felipe.Huici@xxxxxxxxx>;
> Julien Grall <Julien.Grall@xxxxxxx>; Kaly Xin (Arm Technology China)
> <Kaly.Xin@xxxxxxx>
> Subject: Re: [UNIKRAFT PATCH v6 6/7] arch/arm64: Implement bitops for
> arm64
> 
> Reviewed-by: Santiago Pagani <santiago.pagani@xxxxxxxxx>
> 
> On 22.10.19, 09:43, "Jia He" <justin.he@xxxxxxx> wrote:
> 
>     Without this patch, compiler will report warning as follows:
>       In file included from plat/common/arm/time.c:41:0:
>     include/uk/bitops.h: In function 'uk_get_count_order':
>     include/uk/bitops.h:89:10: warning: implicit declaration of function
>     'ukarch_fls'; did you mean 'ukarch_ffsl'? 
> [-Wimplicit-function-declaration]
>       order = ukarch_fls(count);
>               ^~~~~~~~~~
>               ukarch_ffsl
>     include/uk/bitops.h: In function 'uk_find_last_bit':
>     include/uk/bitops.h:154:18: warning: implicit declaration of function
>     'ukarch_flsl'; did you mean 'ukarch_ffsl'? 
> [-Wimplicit-function-declaration]
>         return (bit + ukarch_flsl(mask));
>                       ^~~~~~~~~~~
>                       ukarch_ffsl
> 
>     Signed-off-by: Jia He <justin.he@xxxxxxx>
>     ---
>     V6: change the returned bit postion from [1...32] to [0...31]
> 
>      arch/arm/arm64/include/uk/asm/atomic.h | 36
> ++++++++++++++++++++++++++
>      1 file changed, 36 insertions(+)
> 
>     diff --git a/arch/arm/arm64/include/uk/asm/atomic.h
> b/arch/arm/arm64/include/uk/asm/atomic.h
>     index 7ee6667..431ac84 100644
>     --- a/arch/arm/arm64/include/uk/asm/atomic.h
>     +++ b/arch/arm/arm64/include/uk/asm/atomic.h
>     @@ -37,6 +37,31 @@
>      #error Do not include this header directly
>      #endif
> 
>     +/**
>     + * ukarch_ffs - find first (lowest) set bit in word.
>     + * @word: The word to search
>     + *
>     + * Returns one plus the index of the least significant 1-bit of x, or
>     + * if x is zero, returns zero.
>     + * ffs(1)=0, ffs(0x8000000)=31
>     + */
>     +static inline unsigned int ukarch_ffs(unsigned int x)
>     +{
>     + return __builtin_ffs(x) - 1;
>     +}
>     +
>     +/**
>     + * ukarch_fls - find last (highest) set bit in word.
>     + * @word: The word to search
>     + *
>     + * Undefined if no bit exists, so code should check against 0 first.
>     + * fls(1)=0, fls(0x8000000)=31
>     + */
>     +static inline unsigned int ukarch_fls(unsigned int x)
>     +{
>     + return sizeof(x) * 8 - __builtin_clz(x) - 1;
>     +}
>     +
>      /**
>       * ukarch_ffsl - find first (lowest) set bit in word.
>       * @word: The word to search
>     @@ -68,3 +93,14 @@ static inline unsigned long ukarch_ffsl(unsigned
> long word)
> 
>       return 63 - clz;
>      }
>     +
>     +/**
>     + * ukarch_flsl - find last (highest) set bit in word.
>     + * @word: The word to search
>     + *
>     + * Undefined if no bit exists, so code should check against 0 first.
>     + */
>     +static inline unsigned long ukarch_flsl(unsigned long x)
>     +{
>     + return sizeof(x) * 8 - __builtin_clzl(x) - 1;
>     +}
>     --
>     2.17.1
> 
> 

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