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Re: default mtp in case arm
raju goruganti <raju.goruganti@gmail.com> writes:
> On Tue, Jan 4, 2011 at 4:33 AM, Ian Lance Taylor <iant@google.com> wrote:
>> raju goruganti <raju.goruganti@gmail.com> writes:
>>
>>> Just I want to know ,Whether the dafult for '-mtp' is soft or not?
>>>
>>> If yes ,Why it has been Âchoosen as soft?
>>>
>>> I think mtp=cp15 Âis more efficient(I figured this out after some
>>> google -search).
>>
>> From the friendly manual:
>>
>> `-mtp=NAME'
>> Â Â Specify the access model for the thread local storage pointer.
>> Â Â The valid models are `soft', which generates calls to
>> Â Â `__aeabi_read_tp', `cp15', which fetches the thread pointer from
>> Â Â `cp15' directly (supported in the arm6k architecture), and `auto',
>> Â Â which uses the best available method for the selected processor.
>> Â Â The default setting is `auto'.
>>
>> Ian
>>
> Thank you for your reply,
> Yes,default is auto, and auto chooses soft in latest gcc.
It depends on what processor the compiler has been configured for, and
it will change based on the -march option.
Ian