crosscompiler and porting notes

[Wenqi Chen]

forgot to mention the compiler revision: codesourcery arm2008q3



2009/5/19 Wenqi Chen <cwenqi at gmail.com>:
> codesourcery revison of GCC-4.3 does seem to support armv7-a compiler
> flag/NEON instruction set.
>
> 2009/5/19 Mark Tinguely <tinguely at casselton.net>:
>>
>> sorry for the blank reply. It should have said
>>
>> Looking at the current sources for the GNU assembler, it appears to me that
>> the "gas" sources do not have some new and important ARMv7 commands such as
>> "dmb", "dsb", and "isb" (barriers). There ARMv6 equivalent command, but
>> are not recommended.
>>                        ---
>> I looked at the Cortex document, the first thing that changed in ARMv7
>> is the information registers (for example information on the caches).
>> You will need to replace the CPU information and intialization code.
>>
>> It would be nice to get an ARMv7 ARM. Someone with authority, like the
>> FreeBSD Foundation may be needed.
>>                        ---
>> You will need to write a new cpufunc_asm_XXX.S file of routines. The
>> existing routines assume the pmap will flush the caches on context change.
>>                        ---
>> I would suggest you start by using the existing memory model of flushing
>> caches on context changes until we learn more on the Cortex cache - are they
>> *really* not effected by the cache coloring problem.
>>
>> If you can get the console working, and are willing to put some test
>> code into somewhere like pmap_bootstrap(), to test if the cache coloring
>> is really fixed, I would write it up.
>>                        ---
>> I have some rough code for the new ARMv6/ARMv7 TLS registers, the tlb ASID
>> and load and store exclusive. You have plenty to do to get the board up
>> to single user, without having to worry about this other stuff.
>>
>> --Mark.
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>>
>
>
>
> --
> WC
>



-- 
WC