[U-Boot] [PATCH v2] x86: Import the glibc memset implementation

[Graeme Russ]

On Wed, Nov 9, 2011 at 12:15 PM, Gabe Black <gabeblack at google.com> wrote:
>
>
> On Tue, Nov 8, 2011 at 5:10 PM, Graeme Russ <graeme.russ at gmail.com> wrote:
>>
>> Hi Gabe,
>>
>> first up - Please stop top-posting
>>
>> On Wed, Nov 9, 2011 at 11:59 AM, Gabe Black <gabeblack at chromium.org>
>> wrote:
>> > I'm pretty sure u-boot doesn't link with glibc. I'd expect that to cause
>> > all
>> > sorts of problems on top of being really big. There are default, generic
>> > implementations which it can use, or you can specialize them to take
>> > advantage of architecture specific features like I'm doing here.
>>
>> Hmm,
>>
>> # Add GCC lib
>> ifdef USE_PRIVATE_LIBGCC
>> ifeq ("$(USE_PRIVATE_LIBGCC)", "yes")
>> PLATFORM_LIBGCC = $(OBJTREE)/arch/$(ARCH)/lib/libgcc.o
>> else
>> PLATFORM_LIBGCC = -L $(USE_PRIVATE_LIBGCC) -lgcc
>> endif
>> else
>> PLATFORM_LIBGCC := -L $(shell dirname `$(CC) $(CFLAGS)
>> -print-libgcc-file-name`) -lgcc
>> endif
>> PLATFORM_LIBS += $(PLATFORM_LIBGCC)
>> export PLATFORM_LIBS
>>
>> So we link with libgcc - In another email I raise the question of why
>> regparm is not conflicting here
>>
>> And why do we have an option to not link to libgcc, but on the other
>> hand we never link to libc - I'm confused
>>
>> Regards,
>>
>> Graeme
>>
>
> I don't understand the question. regparm did conflict, which is the point of

Only on 64-bit operations - surely there are other libgcc functions
not covered by your patch. And why had I not seen these before - was
is a case of never hitting that call path?

> my other patch. Why would having an option to link libgcc have anything to
> do with glibc? U-Boot has its own partial libc implementation which has
> generic implementations of certain functions which can be overridden. By not

My point is, why does U-Boot implement parts of libgcc so as to not
link to libgcc, but uses (by default) glibc - Why not always implement
both, or always (by default) link to both?

> linking to the generic implementation and providing a specialized one, the
> performance improves two fold. Those are the two choices.

Regards,

Graeme