ldrb vs ldrh in gcc-3.4.4 (ARM)

[Steven Scholz]

Richard,

>>>First google hit on "AT91RM9200":
>>>	http://www.atmel.com/dyn/products/product_card.asp?part_id=2983
>>>
>>>That page mentions that it's an ARM920T core.  First google hit on
>>>"ARM920T":
>>>	http://www.arm.com/products/CPUs/ARM920T.html
>>>
>>>That page mentions 'ARMv4T'.
>>
>>Thanks for googling for me! ;-)
>>
>>So I use either -march=armv4 _OR_ -mcpu=arm920t. Right?
>>
>>(Using both brought me a warning about conflicting).
> 
> 
> the arm920t is an armv4t device (the 't' is thumb).
> 
> Basically, there are two options, -march=xxx and -mtune=xxx that are
> independent (one selects the available instructions, the other the best
> way to use that set for the intended cpu).  -mcpu=xxx is shorthand that
> can be used to set both options in one go: so -mcpu=xxx is equivalent to
> writing -march=<arch_of(xxx)> -mtune=xxx.
> 
> Note that to get Thumb code you have to use -mthumb; it's not sufficient
> to tell the compiler that you have thumb instructions available.

Thanks a million. Maybe you could explain the difference of arm920t and arm9tdmi 
as well, please?

--
Steven

------
Want more information?  See the CrossGCC FAQ, http://www.objsw.com/CrossGCC/
Want to unsubscribe? Send a note to crossgcc-unsubscribe@sources.redhat.com