Lpc2000

David Hawkins wrote:

>Tom Walsh wrote:
>
>  
>
>>>So, I never used bit-fields again ...
>>>      
>>>
>
>Ok, So 'I never had a reason to use bit-fields since then' :)
>
>  
>
>>Bitfields are usefull for tearing apart bit-packed fields within data or 
>>assembling it.  While you are correct in stating that use of a bitfield 
>>against a register which expects a finite length operation (32 bit in 
>>your case), it is not correct to condemn then out of hand just because 
>>you had a bad experience.  "you burn you learn"...
>>    
>>
>
>Yes, this was definitely a learning experience - one I am sure
>others will face - except perhaps for those reading this
>thread.
>
>Thanks for the pointers on legitimate uses of bit-fields.
>
>Here's a question for you. What happens on different-endianness
>machines regarding bit-fields? Eg. lets say you analyze FAT headers
>(which was discussed a few emails back). If I recall correctly,
>they used bitfields and packed structures.
>
>Do the layouts of entries match on different endianness machines,
>or do you have to be careful there too?
>
>  
>
There has been much written about problems with Big-Endian processors 
and thier data, esp with type conversions.  I'll stick to Little-Endian.


TomW

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>


-- 
Tom Walsh - WN3L - Embedded Systems Consultant
http://openhardware.net, http://cyberiansoftware.com
"Windows? No thanks, I have work to do..."
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