[U-Boot] [PATCH 13/17] post/i2c: Add ability to ignore I2C devices
Sergei Shtylyov
sshtylyov at mvista.com
Thu Sep 30 18:36:34 CEST 2010
Hello.
Peter Tyser wrote:
>>>>>> +#ifdef I2C_ADDR_IGNORE_LIST
>>>>>> + unsigned char i2c_ignore_list[] = I2C_ADDR_IGNORE_LIST;
>>>>> This array is aking to be *static*...
>>>> ... and *const* as well ?
>>> I'll add 'const' in the next version, but I'm not sure if the 'static'
>>> adds any benefit since its a local variable.
>> Have you considered the amount of code needed for non-static array
>> initialization?
> I think I did:) I'd think a const array would generate nearly identical
> code with or without the static qualifier. In either case the function
> will load a pointer to the array and loop through it. The array should
> be stored in the data section of the U-Boot binary so I'm not sure how
> the array initialization differs. I did a quick comparison for this
> specific case and the resulting sizes came out the same:
> ptyser at petert u-boot $ size ./i2c-static.o
> text data bss dec hex filename
> 347 12 0 359 167 ./i2c-static.o
> ptyser at petert u-boot $ size ./i2c-nonstatic.o
> text data bss dec hex filename
> 347 12 0 359 167 ./i2c-nonstatic.o
> Is there something I'm overlooking?
If 'const' alone makes it go into the data section, then no. I didn't think
it does.
> Regards,
> Peter
WBR, Sergei
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