Building newlib and gcc for ARM Thumb2

Rob Emanuele
Wed Feb 4 00:18:00 GMT 2009


In my case:

[rje@rje-pc xxxxx]$ arm-eabi-gcc --print-multi-lib

This proves I am missing that multilib.  How would I go about creating it?

Thank you,


On Tue, Feb 3, 2009 at 1:41 PM, Jeff Johnston <> wrote:
> Regarding building newlib, you should know about multilibs.  Multilibs are
> versions of the library
> built with specific options.  The compiler determines what multilibs should
> exist and how to build them.
> The compiler has an option: --print-multi-lib which specifies the various
> permutations
> of options to build the library with and what subdirectories to put them
> under.  Newlib issues this
> option to determine how many multilibs to build and how to do it.
> For example, the mn10300-elf-gcc compiler I have on my system gives:
> [jjohnstn@vermillion]$ ./mn10300-elf-gcc --print-multi-lib
> .;
> am33;@mam33
> am33-2;@mam33-2
> am34;@mam34
> Note that this indicates there are 3 additional multilibs in addition to the
> default library (.;).  The
> am33 version of the library uses a subdirectory named "am33" and is compiled
> with the -mam33 option, the am33-2 is built with -mam33-2, etc...  Sometimes
> you have permutations and can end up with nested subdirectories (e.g. a
> bigendian and soft-float library could be stored under a subdirectory
> be/sf).
> When you compile/link an application via gcc and specify a particular
> multilib option, the compiler will try and
> find the library under the specified subdirectory or subdirectories of the
> location where newlib has been specified to be.  This does not occur if you
> do the link yourself via ld (you have to figure out where the library has
> been stored).
> So, check to see if the compiler you are ultimately using in the newlib
> build has a thumb2 multilib and the option(s) used (via --print-multi-lib).
>  Then, verify that the compiler is setting the __thumb2__ flag when this
> particular option is chosen which is what ultimately determines if the
> thumb2-specific code in setjmp.S is being activated properly.
> -- Jeff J.
> Rob Emanuele wrote:
>> Alexandre,
>> Yes, it builds but I don't see any code generated for thumb2.  I see
>> ARM and thumb but not thumb2.
>> --Rob
>> On Tue, Feb 3, 2009 at 9:14 AM, Alexandre Pereira Nunes
>> <> wrote:
>>> On Sun, Feb 1, 2009 at 4:52 PM, Rob Emanuele <> wrote:
>>>> Greetings,
>>>> I'm trying to build newlib and gcc for a Cortex-M3 processor.  What
>>>> are the best ways for doing this?  I'm running into a problem with the
>>>> "setjmp" call as it is not being compiled correctly for Thumb2.  It is
>>>> only being compiled for Thumb.  Are there a set of instructions on the
>>>> proper build procedure to get all the libs built for arm, thumb, and
>>>> thumb2?
>>>> Thanks,
>>>> Rob Emanuele
>>> Are you trying 1.17.0 ? It should build fine.

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