ARM Thumb mode size increase by enabling -mthumb mode

[naveen yadav]

On Mon, Aug 10, 2009 at 9:57 PM, naveen yadav<yad.naveen@gmail.com> wrote:
> Hi Andrew,
>
>
> I want to know in which cases size of binary or .o file increase by
> enabling -mthumb mode.
>
> I have observed in one open source program iozone. i found that if i
> pass -mthumb option size of binary increases.
>
> I do not understand why ..
>
> will you pls help
>
> Best Regards
>
>
> On Mon, Aug 10, 2009 at 9:51 PM, Andrew Haley<aph@redhat.com> wrote:
>> naveen yadav wrote:
>>
>>> we have observed few points,
>>>
>>> 1. In Some cases size of .o file increase in thumb mode. when i
>>> dissamble it i found all instruction are 16 bit.In what cases size increases?
>>
>> Did you not find out by looking at gcc's output?  What did you
>> see?
>>
>>> 2. How much size will be reduce as compared with ARM mode.?
>>
>>> 3. Code reduction depends on what ?
>>>
>>> 4. How much performance effect with Arm and Thumb mode.
>>
>> See www.arm.com/pdfs/Thumb-2CoreTechnologyWhitepaper-Final4.pdf
>>
>> Andrew.
>>
>>
>