[U-Boot] [PATCH 1/3] spl: ram: Do not memcpy() identical buffers

Marek Vasut marex at denx.de
Tue May 28 02:44:52 UTC 2019


On 5/28/19 4:42 AM, Tom Rini wrote:
> On Tue, May 28, 2019 at 04:07:44AM +0200, Marek Vasut wrote:
>> On 5/28/19 4:06 AM, Tom Rini wrote:
>>> On Tue, May 28, 2019 at 03:49:13AM +0200, Marek Vasut wrote:
>>>
>>>> If the source and destination buffer address is identical, there is
>>>> no need to memcpy() the content. Skip the memcpy() in such a case.
>>>>
>>>> Signed-off-by: Marek Vasut <marex at denx.de>
>>>> Cc: Michal Simek <michal.simek at xilinx.com>
>>>> Cc: Tom Rini <trini at konsulko.com>
>>>
>>> Shouldn't memcpy catch that itself?
>>>
>> memcpy(3) says
>>        The memcpy() function copies n bytes from memory area src to
>> memory area dest.  The memory areas must not overlap.  Use memmove(3) if
>> the memory areas do overlap.
> 
> OK, and shouldn't memcpy optimize that case?  Does it usually?

As the manpage says "The memory areas must not overlap." , I would
expect it does not have to ?

-- 
Best regards,
Marek Vasut


More information about the U-Boot mailing list