This is the mail archive of the crossgcc@sourceware.org mailing list for the crossgcc project.

See the CrossGCC FAQ for lots more information.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: How to request -mthumb to be applied to all tools built for arm


Lev, All,

On Wednesday 06 January 2010 14:39:02 lev@lingnu.com wrote:
> I am withdrawing my question about making -mthumb default compilation
> option, and here comes the the question - how to specify
> compilation/configuration options to the tools which are a part of
> toolchain,

It's seldom used, but you have:
  CT_TARGET_CFLAGS
  CT_TARGET_LDFLAGS

> Suppose I want to build libstc++ using -mthumb, how can this be achieved ?
> I was trying to change manually Makefile.am in the
> targets/src/gcc-4.4.1/libstdc++-v3/src/Makefile.am  but it does not copied
> the -mthumb to the generated Makefile in the build area.

And for the special case gcc is, the following variable is indeed used
to build libstdc++:
  CT_CC_ENABLE_CXX_FLAGS

> > I know the guys at ARM managed to build a Linux kernel using pure Thumb2,
> > and that it's now mainline, but so far I have not seen any 'Linux' libc
> > build in pure Thumb mode.
>   I am not sure , -mthumb produced Thumb2 assembly ?

Base on the correct processor passed as -mcpu, yes, -mthumb will generate
proper Thumb2 insns. Eg. if you pass: -mcpu=cortex-m3 -mthumb

Thumb2 is just plain Thumb, plus a few other insns, but hose new ones
will probably be used only in a kernel (eg. interrupt handling...). But
I'm no Thumb2 expert... :-/

Regards,
Yann E. MORIN.

-- 
.-----------------.--------------------.------------------.--------------------.
|  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
| +33 223 225 172 `------------.-------:  X  AGAINST      |  \e/  There is no  |
| http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL    |   v   conspiracy.  |
`------------------------------^-------^------------------^--------------------'



--
For unsubscribe information see http://sourceware.org/lists.html#faq


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]