ARM processor and gcc

ARM processor and gcc

[ranjith kumar]

Hi,
      I have ARM11 processor(ARMv6).
  It has thumb and Jazelle extension.

So there are three kinds of machine instruction sets
a) ARM instruction set
b) Thumb instruction set
c)Jazelle instruction set



1) How to tell GCC to produce the executable with Tumb instruction set
or Jazelle instruction  set only??
2) Jazelle instruction are produced for Java programs only. Not for
C/C++. right???
3) Suppose my program(single file) has 3 functions. How to generate
function1 code with ARM instruction set
  and function2 code with Thumb instruction set and/or function3 code
with Jazelle instruction set??

Thanks in advance.

P.S: I tried with "man gcc". I could not get any clue.

Re: ARM processor and gcc

[Ian Lance Taylor]

ranjith kumar <ranjithproxy@gmail.com> writes:

> 1) How to tell GCC to produce the executable with Tumb instruction set
> or Jazelle instruction  set only??

To get Thumb instructions, use -mthumb.  gcc does not generate the
Jazelle instruction set.


> 2) Jazelle instruction are produced for Java programs only. Not for
> C/C++. right???

That is my understanding, yes.


> 3) Suppose my program(single file) has 3 functions. How to generate
> function1 code with ARM instruction set
>   and function2 code with Thumb instruction set and/or function3 code
> with Jazelle instruction set??

As far as I know that is not supported for ARM/Thumb.  There is
similar functionality for MIPS/MIPS16, and no doubt it will be
supported for ARM/Thumb soon enough.


> P.S: I tried with "man gcc". I could not get any clue.

Try http://gcc.gnu.org/onlinedocs/ .

Ian