[U-Boot-Users] Re: GOT and adresses

[U-Boot-Users] Re: GOT and adresses

[Federico Lucifredi]

Hello All,
 I am porting U-boot to an MPC8247-based custom board. I Got my arms around the
 TOC issue (thanks Wolfgang), but I am also trying to look at the GOT: I 
understand from the  documentation that I should not worry/need to touch that, 
but just in case, I want to make sure I understand what it is doing.

 I am having trouble finding documentation on how the .GOT entries are
customized in gcc as they are in the u-boot sources... any pointers?

 -F
_________________________________________
-- "'Problem' is a bleak word for challenge" - Richard Fish

Muad'Dib of Caladan (Federico L. Lucifredi)- Harvard University & BU
http://metcs.bu.edu/~lucifred

[U-Boot-Users] Re: GOT and adresses

[Wolfgang Denk]

In message <W8483322004145761102085351@webmail2> you wrote:
>
>  I am having trouble finding documentation on how the .GOT entries are
> customized in gcc as they are in the u-boot sources... any pointers?

I'm not sure what you mean by "customized in gcc". The GNU  toolchain
just  uses  the  standard  ABI  definitions.  See section "5. PROGRAM
LOADING AND DYNAMIC LINKING",  and  especially  sub-section  "Dynamic
Linking   -  Global  Offset  Table"  in  the  PowerPC  Processor  ABI
Supplement (see http://www.denx.de/twiki/bin/view/Training/MoreInformationMoreLinks
for a link).

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Any technology distinguishable from magic is insufficiently advanced.

[U-Boot-Users] Re: GOT and adresses

[Federico Lucifredi]

Hello WD,

> I'm not sure what you mean by "customized in gcc". The GNU  toolchain
> just  uses  the  standard  ABI  definitions.  See section "5. PROGRAM
> LOADING AND DYNAMIC LINKING",  and  especially  sub-section  "Dynamic
> Linking   -  Global  Offset  Table"  in  the  PowerPC  Processor  ABI
> Supplement (see http://www.denx.de/twiki/bin/view/Training/MoreInformationMoreLinks
> for a link).

Yes, I have read that, but u-boot somehow alters the GOT behavior provided by gcc with macros such as GET_GOT. I am not sure why that is necessary, or, in other words, why the macro is there in the first place.

-F

[U-Boot-Users] Re: GOT and adresses

[Wolfgang Denk]

In message <W39693260161781102304127@webmail2> you wrote:
> 
> Yes, I have read that, but u-boot somehow alters the GOT behavior provided by gcc with macros such as GET_GOT. I am not sure why that is necessary, or, in other words, why the macro is there in the first place.

Please use a standard line length, i. e. a maximum of 70 characters per line.


We don't "alter GOT behaviour". We just use the GOT to  relocate  the
code to a new address. This is something which has nothing to do with
GCC.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
One of the advantages of being a captain is being able to ask for ad-
vice without necessarily having to take it.
	-- Kirk, "Dagger of the Mind", stardate 2715.2