Re: [PATCH] 2.4.21-rc1 pointless IDE noise reduction

[Timothy Miller]

Richard B. Johnson wrote:

>On Thu, 24 Apr 2003, Chuck Ebbert wrote:
>
>  
>
>>Jens Axboe wrote:
>>
>>
>>    
>>
>>>>+	return((drive->id->cfs_enable_1 & 0x0400) ? 1 : 0);
>>>> }
>>>>        
>>>>
>>>Seconded, it causes a lot more confusion than it does good.
>>>      
>>>
>>  The return looks like a function call in that last line.
>>
>>  That's one of the few things I find really annoying -- extra parens
>>are fine when they make code clearer, but not there.
>>
>>
>>-------
>> Chuck [ C Style Police, badge #666 ]
>>    
>>
>
>return((drive->id->cfs_enable_1 & 0x0400) ? 1 : 0);
>                                  ^^^^^^|__________ wtf?
>These undefined numbers in the code are much more annoying to me...
>but I don't have a C Style Police Badge.
>
>Also, whatever that is, 0x400, I'll call it MASK, can have shorter
>code like:
>
>   return (drive->id->cfs_enable_1 && MASK); // TRUE/FALSE
>... for pedantics...
>   return (int) (drive->id->cfs_enable_1 && MASK);
>
>
>  
>

That wouldn't work, because && isn't a bitwise operator.  But I agree 
that the ( x ? 1 : 0 ) method may not be very efficient, because it may 
involve branches.

Two alternatives:

(a)     !!(x & 0x400)

(b)     (x & 0x400) >> 10